diff --git a/docs/.DS_Store b/docs/.DS_Store
new file mode 100644
index 00000000..60a78faf
Binary files /dev/null and b/docs/.DS_Store differ
diff --git a/docs/ERD_v2_improved.txt b/docs/ERD_v2_improved.txt
index 9552844f..03d6d546 100644
--- a/docs/ERD_v2_improved.txt
+++ b/docs/ERD_v2_improved.txt
@@ -66,6 +66,9 @@ Table lessons {
   content jsonb [note: 'multi-language lesson content']
   type varchar [not null, note: 'video | pdf | text | quiz']
   sort_order int [not null, default: 0, note: 'must be >= 0']
+  is_sequential boolean [not null, default: true, note: 'require previous lessons to be completed']
+  prerequisite_lesson_ids jsonb [note: 'array of lesson IDs that must be completed first, e.g. [1, 2, 3]']
+  require_pass_quiz boolean [default: false, note: 'require passing quiz to unlock next lessons']
   created_at datetime [not null, default: `now()`]
   updated_at datetime [not null, default: `now()`]
   
@@ -214,6 +217,23 @@ Table announcement_attachments {
   }
 }
 
+Table lesson_attachments {
+  id int [pk, increment]
+  lesson_id int [not null, ref: > lessons.id]
+  file_name varchar [not null]
+  file_path varchar [not null, note: 'S3 key or file path']
+  file_size int [not null, note: 'in bytes']
+  mime_type varchar [not null]
+  description jsonb [note: 'multi-language description']
+  sort_order int [not null, default: 0]
+  created_at datetime [not null, default: `now()`]
+  
+  indexes {
+    lesson_id
+    (lesson_id, sort_order)
+  }
+}
+
 Table orders {
   id int [pk, increment]
   user_id int [not null, ref: > users.id]
diff --git a/docs/api-docs/api_attachments_examples.md b/docs/api-docs/api_attachments_examples.md
new file mode 100644
index 00000000..303f5704
--- /dev/null
+++ b/docs/api-docs/api_attachments_examples.md
@@ -0,0 +1,520 @@
+# API Usage Examples - Lesson Attachments
+
+## 📎 Lesson Attachments Endpoints
+
+---
+
+## 1. Upload Attachment (Instructor)
+
+### POST `/instructor/courses/:courseId/lessons/:lessonId/attachments`
+
+#### Request:
+```http
+POST /api/instructor/courses/1/lessons/5/attachments
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+Content-Type: multipart/form-data
+
+file: <slides.pdf>
+description_th: "สไลด์ประกอบการสอน"
+description_en: "Lecture slides"
+sort_order: 1
+```
+
+#### Response 201:
+```json
+{
+  "id": 10,
+  "lesson_id": 5,
+  "file_name": "slides.pdf",
+  "file_path": "lessons/5/slides.pdf",
+  "file_size": 2048576,
+  "mime_type": "application/pdf",
+  "description": {
+    "th": "สไลด์ประกอบการสอน",
+    "en": "Lecture slides"
+  },
+  "sort_order": 1,
+  "download_url": "/api/lessons/5/attachments/10/download",
+  "created_at": "2024-12-23T15:00:00Z"
+}
+```
+
+#### Response 422 (File Too Large):
+```json
+{
+  "error": {
+    "code": "FILE_TOO_LARGE",
+    "message": "File size exceeds maximum limit of 100 MB",
+    "file_size": 104857600,
+    "max_size": 104857600
+  }
+}
+```
+
+#### Response 422 (Too Many Attachments):
+```json
+{
+  "error": {
+    "code": "MAX_ATTACHMENTS_EXCEEDED",
+    "message": "Maximum 10 attachments per lesson",
+    "current_count": 10,
+    "max_count": 10
+  }
+}
+```
+
+#### Response 422 (Invalid File Type):
+```json
+{
+  "error": {
+    "code": "INVALID_FILE_TYPE",
+    "message": "File type not allowed",
+    "mime_type": "application/x-executable",
+    "allowed_types": ["application/pdf", "application/zip", "image/jpeg", "..."]
+  }
+}
+```
+
+---
+
+## 2. List Attachments (Instructor)
+
+### GET `/instructor/courses/:courseId/lessons/:lessonId/attachments`
+
+#### Request:
+```http
+GET /api/instructor/courses/1/lessons/5/attachments
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 200:
+```json
+{
+  "lesson_id": 5,
+  "attachments": [
+    {
+      "id": 10,
+      "file_name": "slides.pdf",
+      "file_size": 2048576,
+      "mime_type": "application/pdf",
+      "description": {
+        "th": "สไลด์ประกอบการสอน",
+        "en": "Lecture slides"
+      },
+      "sort_order": 1,
+      "download_url": "/api/lessons/5/attachments/10/download",
+      "created_at": "2024-12-23T15:00:00Z"
+    },
+    {
+      "id": 11,
+      "file_name": "code.zip",
+      "file_size": 512000,
+      "mime_type": "application/zip",
+      "description": {
+        "th": "โค้ดตัวอย่าง",
+        "en": "Sample code"
+      },
+      "sort_order": 2,
+      "download_url": "/api/lessons/5/attachments/11/download",
+      "created_at": "2024-12-23T15:05:00Z"
+    },
+    {
+      "id": 12,
+      "file_name": "exercises.docx",
+      "file_size": 256000,
+      "mime_type": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+      "description": {
+        "th": "แบบฝึกหัด",
+        "en": "Exercises"
+      },
+      "sort_order": 3,
+      "download_url": "/api/lessons/5/attachments/12/download",
+      "created_at": "2024-12-23T15:10:00Z"
+    }
+  ],
+  "total": 3
+}
+```
+
+---
+
+## 3. Update Attachment Info (Instructor)
+
+### PUT `/instructor/courses/:courseId/lessons/:lessonId/attachments/:attachmentId`
+
+#### Request:
+```http
+PUT /api/instructor/courses/1/lessons/5/attachments/10
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+Content-Type: application/json
+
+{
+  "description": {
+    "th": "สไลด์ประกอบการสอน (ฉบับแก้ไข)",
+    "en": "Lecture slides (revised)"
+  },
+  "sort_order": 2
+}
+```
+
+#### Response 200:
+```json
+{
+  "id": 10,
+  "lesson_id": 5,
+  "file_name": "slides.pdf",
+  "file_size": 2048576,
+  "mime_type": "application/pdf",
+  "description": {
+    "th": "สไลด์ประกอบการสอน (ฉบับแก้ไข)",
+    "en": "Lecture slides (revised)"
+  },
+  "sort_order": 2,
+  "updated_at": "2024-12-23T15:20:00Z"
+}
+```
+
+---
+
+## 4. Delete Attachment (Instructor)
+
+### DELETE `/instructor/courses/:courseId/lessons/:lessonId/attachments/:attachmentId`
+
+#### Request:
+```http
+DELETE /api/instructor/courses/1/lessons/5/attachments/10
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 204:
+```
+No Content
+```
+
+---
+
+## 5. Reorder Attachments (Instructor)
+
+### PUT `/instructor/courses/:courseId/lessons/:lessonId/attachments/reorder`
+
+#### Request:
+```http
+PUT /api/instructor/courses/1/lessons/5/attachments/reorder
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+Content-Type: application/json
+
+{
+  "attachments": [
+    { "id": 11, "sort_order": 1 },
+    { "id": 12, "sort_order": 2 },
+    { "id": 10, "sort_order": 3 }
+  ]
+}
+```
+
+#### Response 200:
+```json
+{
+  "message": "Attachments reordered successfully",
+  "attachments": [
+    {
+      "id": 11,
+      "file_name": "code.zip",
+      "sort_order": 1
+    },
+    {
+      "id": 12,
+      "file_name": "exercises.docx",
+      "sort_order": 2
+    },
+    {
+      "id": 10,
+      "file_name": "slides.pdf",
+      "sort_order": 3
+    }
+  ]
+}
+```
+
+---
+
+## 6. Get Lesson with Attachments (Student)
+
+### GET `/students/courses/:courseId/lessons/:lessonId`
+
+**Changes**: เพิ่ม `attachments` array
+
+#### Request:
+```http
+GET /api/students/courses/1/lessons/5
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 200:
+```json
+{
+  "id": 5,
+  "title": "บทที่ 3: ทฤษฎี",
+  "content": "<p>เนื้อหาบทเรียน...</p>",
+  "type": "video",
+  "video_url": "https://cdn.example.com/videos/lesson-5.m3u8",
+  "duration": "00:25:00",
+  "is_completed": false,
+  "can_access": true,
+  
+  "attachments": [
+    {
+      "id": 11,
+      "file_name": "code.zip",
+      "file_size": 512000,
+      "mime_type": "application/zip",
+      "description": "โค้ดตัวอย่าง",
+      "download_url": "/api/lessons/5/attachments/11/download"
+    },
+    {
+      "id": 12,
+      "file_name": "exercises.docx",
+      "file_size": 256000,
+      "mime_type": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+      "description": "แบบฝึกหัด",
+      "download_url": "/api/lessons/5/attachments/12/download"
+    },
+    {
+      "id": 10,
+      "file_name": "slides.pdf",
+      "file_size": 2048576,
+      "mime_type": "application/pdf",
+      "description": "สไลด์ประกอบการสอน",
+      "download_url": "/api/lessons/5/attachments/10/download"
+    }
+  ]
+}
+```
+
+---
+
+## 7. Download Attachment
+
+### GET `/lessons/:lessonId/attachments/:attachmentId/download`
+
+#### Request:
+```http
+GET /api/lessons/5/attachments/10/download
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 200:
+```http
+HTTP/1.1 200 OK
+Content-Type: application/pdf
+Content-Disposition: attachment; filename="slides.pdf"
+Content-Length: 2048576
+
+<binary file data>
+```
+
+#### Response 403 (Not Enrolled):
+```json
+{
+  "error": {
+    "code": "NOT_ENROLLED",
+    "message": "You must enroll in this course to download attachments",
+    "course_id": 1
+  }
+}
+```
+
+---
+
+## Frontend Integration Examples
+
+### 1. Upload Attachment Component
+
+```javascript
+async function uploadAttachment(courseId, lessonId, file, description) {
+  const formData = new FormData();
+  formData.append('file', file);
+  formData.append('description_th', description.th);
+  formData.append('description_en', description.en);
+  formData.append('sort_order', 1);
+  
+  try {
+    const response = await fetch(
+      `/api/instructor/courses/${courseId}/lessons/${lessonId}/attachments`,
+      {
+        method: 'POST',
+        headers: {
+          'Authorization': `Bearer ${token}`
+        },
+        body: formData
+      }
+    );
+    
+    if (!response.ok) {
+      const error = await response.json();
+      
+      if (error.error.code === 'FILE_TOO_LARGE') {
+        showAlert('ไฟล์ใหญ่เกินไป (สูงสุด 100 MB)');
+      } else if (error.error.code === 'MAX_ATTACHMENTS_EXCEEDED') {
+        showAlert('แนบไฟล์ได้สูงสุด 10 ไฟล์');
+      } else if (error.error.code === 'INVALID_FILE_TYPE') {
+        showAlert('ประเภทไฟล์ไม่รองรับ');
+      }
+      return;
+    }
+    
+    const data = await response.json();
+    showSuccess('อัปโหลดไฟล์สำเร็จ');
+    return data;
+  } catch (error) {
+    console.error('Upload error:', error);
+    showAlert('เกิดข้อผิดพลาดในการอัปโหลด');
+  }
+}
+```
+
+### 2. Display Attachments List
+
+```javascript
+function AttachmentsList({ attachments }) {
+  return (
+    <div className="attachments-list">
+      <h3>📎 ไฟล์แนบ ({attachments.length})</h3>
+      
+      {attachments.map(attachment => (
+        <div key={attachment.id} className="attachment-item">
+          <div className="file-icon">
+            {getFileIcon(attachment.mime_type)}
+          </div>
+          
+          <div className="file-info">
+            <div className="file-name">{attachment.file_name}</div>
+            <div className="file-description">{attachment.description}</div>
+            <div className="file-size">{formatFileSize(attachment.file_size)}</div>
+          </div>
+          
+          <a 
+            href={attachment.download_url}
+            download
+            className="download-button"
+          >
+            ⬇ ดาวน์โหลด
+          </a>
+        </div>
+      ))}
+    </div>
+  );
+}
+
+function getFileIcon(mimeType) {
+  if (mimeType.includes('pdf')) return '📄';
+  if (mimeType.includes('zip')) return '📦';
+  if (mimeType.includes('word')) return '📝';
+  if (mimeType.includes('excel')) return '📊';
+  if (mimeType.includes('powerpoint')) return '📊';
+  if (mimeType.includes('image')) return '🖼️';
+  return '📎';
+}
+
+function formatFileSize(bytes) {
+  if (bytes < 1024) return bytes + ' B';
+  if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(1) + ' KB';
+  return (bytes / (1024 * 1024)).toFixed(1) + ' MB';
+}
+```
+
+### 3. Drag & Drop Reorder
+
+```javascript
+function ReorderAttachments({ attachments, onReorder }) {
+  const [items, setItems] = useState(attachments);
+  
+  const handleDragEnd = (result) => {
+    if (!result.destination) return;
+    
+    const reordered = Array.from(items);
+    const [removed] = reordered.splice(result.source.index, 1);
+    reordered.splice(result.destination.index, 0, removed);
+    
+    // Update sort_order
+    const updated = reordered.map((item, index) => ({
+      id: item.id,
+      sort_order: index + 1
+    }));
+    
+    setItems(reordered);
+    onReorder(updated);
+  };
+  
+  return (
+    <DragDropContext onDragEnd={handleDragEnd}>
+      <Droppable droppableId="attachments">
+        {(provided) => (
+          <div {...provided.droppableProps} ref={provided.innerRef}>
+            {items.map((item, index) => (
+              <Draggable key={item.id} draggableId={String(item.id)} index={index}>
+                {(provided) => (
+                  <div
+                    ref={provided.innerRef}
+                    {...provided.draggableProps}
+                    {...provided.dragHandleProps}
+                  >
+                    {item.file_name}
+                  </div>
+                )}
+              </Draggable>
+            ))}
+            {provided.placeholder}
+          </div>
+        )}
+      </Droppable>
+    </DragDropContext>
+  );
+}
+```
+
+---
+
+## Allowed File Types
+
+| Category | MIME Type | Extension |
+|----------|-----------|-----------|
+| **Documents** | `application/pdf` | .pdf |
+| | `application/msword` | .doc |
+| | `application/vnd.openxmlformats-officedocument.wordprocessingml.document` | .docx |
+| | `application/vnd.ms-excel` | .xls |
+| | `application/vnd.openxmlformats-officedocument.spreadsheetml.sheet` | .xlsx |
+| | `application/vnd.ms-powerpoint` | .ppt |
+| | `application/vnd.openxmlformats-officedocument.presentationml.presentation` | .pptx |
+| **Archives** | `application/zip` | .zip |
+| | `application/x-rar-compressed` | .rar |
+| | `application/x-7z-compressed` | .7z |
+| **Images** | `image/jpeg` | .jpg |
+| | `image/png` | .png |
+| | `image/gif` | .gif |
+| **Text** | `text/plain` | .txt |
+| | `text/csv` | .csv |
+
+---
+
+## File Limits
+
+- **Max file size**: 100 MB per file
+- **Max attachments**: 10 files per lesson
+- **Total size**: 500 MB per lesson
+
+---
+
+## Summary
+
+**New Endpoints**: 6
+- `POST /instructor/courses/:courseId/lessons/:lessonId/attachments`
+- `GET /instructor/courses/:courseId/lessons/:lessonId/attachments`
+- `PUT /instructor/courses/:courseId/lessons/:lessonId/attachments/:attachmentId`
+- `DELETE /instructor/courses/:courseId/lessons/:lessonId/attachments/:attachmentId`
+- `PUT /instructor/courses/:courseId/lessons/:lessonId/attachments/reorder`
+- `GET /lessons/:lessonId/attachments/:attachmentId/download`
+
+**Modified Endpoints**: 2
+- `GET /students/courses/:courseId/lessons/:lessonId` - เพิ่ม attachments array
+- `GET /students/courses/:courseId/learn` - เพิ่ม attachments_count
diff --git a/docs/api_endpoints.md b/docs/api-docs/api_endpoints.md
similarity index 88%
rename from docs/api_endpoints.md
rename to docs/api-docs/api_endpoints.md
index 521573d8..5703d818 100644
--- a/docs/api_endpoints.md
+++ b/docs/api-docs/api_endpoints.md
@@ -67,8 +67,9 @@ Authorization: Bearer <token>
 |--------|----------|------|-------------|
 | POST | `/courses/:courseId/enroll` | 👨‍🎓 Student | Enroll in course |
 | GET | `/students/courses` | 👨‍🎓 Student | Get my enrolled courses |
-| GET | `/students/courses/:courseId/learn` | 👨‍🎓 Student | Get course learning page |
-| GET | `/students/courses/:courseId/lessons/:lessonId` | 👨‍🎓 Student | Get lesson content |
+| GET | `/students/courses/:courseId/learn` | 👨‍🎓 Student | Get course learning page (with lock status) |
+| GET | `/students/courses/:courseId/lessons/:lessonId` | 👨‍🎓 Student | Get lesson content (checks prerequisites) |
+| GET | `/students/courses/:courseId/lessons/:lessonId/access-check` | 👨‍🎓 Student | Check lesson access without loading content |
 | POST | `/students/courses/:courseId/lessons/:lessonId/complete` | 👨‍🎓 Student | Mark lesson as complete |
 
 ### Instructor Endpoints
@@ -96,11 +97,22 @@ Authorization: Bearer <token>
 ### Lessons
 | Method | Endpoint | Auth | Description |
 |--------|----------|------|-------------|
-| POST | `/instructor/courses/:courseId/chapters/:chapterId/lessons` | 👨‍🏫 Instructor | Create lesson |
+| POST | `/instructor/courses/:courseId/chapters/:chapterId/lessons` | 👨‍🏫 Instructor | Create lesson (with video & attachments) |
 | PUT | `/instructor/courses/:courseId/lessons/:lessonId` | 👨‍🏫 Instructor | Update lesson |
 | DELETE | `/instructor/courses/:courseId/lessons/:lessonId` | 👨‍🏫 Instructor | Delete lesson |
-| POST | `/instructor/courses/:courseId/lessons/:lessonId/video` | 👨‍🏫 Instructor | Upload video |
 | PUT | `/instructor/courses/:courseId/lessons/reorder` | 👨‍🏫 Instructor | Reorder lessons |
+| GET | `/instructor/courses/:courseId/lessons/:lessonId/prerequisites` | 👨‍🏫 Instructor | View lesson prerequisites |
+| POST | `/instructor/courses/:courseId/lessons/:lessonId/prerequisites` | 👨‍🏫 Instructor | Update lesson prerequisites |
+
+### Lesson Attachments
+| Method | Endpoint | Auth | Description |
+|--------|----------|------|-------------|
+| POST | `/instructor/courses/:courseId/lessons/:lessonId/attachments` | 👨‍🏫 Instructor | Add more attachments |
+| GET | `/instructor/courses/:courseId/lessons/:lessonId/attachments` | 👨‍🏫 Instructor | List attachments |
+| PUT | `/instructor/courses/:courseId/lessons/:lessonId/attachments/:attachmentId` | 👨‍🏫 Instructor | Update attachment info |
+| DELETE | `/instructor/courses/:courseId/lessons/:lessonId/attachments/:attachmentId` | 👨‍🏫 Instructor | Delete attachment |
+| PUT | `/instructor/courses/:courseId/lessons/:lessonId/attachments/reorder` | 👨‍🏫 Instructor | Reorder attachments |
+| GET | `/lessons/:lessonId/attachments/:attachmentId/download` | ✅ | Download attachment |
 
 ---
 
@@ -291,13 +303,13 @@ Authorization: Bearer <token>
 
 ---
 
-## Total Endpoints: **85+**
+## Total Endpoints: **93+**
 
 - Authentication: 6
 - User Management: 4
 - Categories: 5
-- Courses: 11
-- Chapters & Lessons: 9
+- Courses: 12
+- Chapters & Lessons: 16 (-1)
 - Quizzes: 10
 - Announcements: 6
 - Reports: 11
diff --git a/docs/api-docs/api_lesson_creation_simplified.md b/docs/api-docs/api_lesson_creation_simplified.md
new file mode 100644
index 00000000..8bef304c
--- /dev/null
+++ b/docs/api-docs/api_lesson_creation_simplified.md
@@ -0,0 +1,306 @@
+# Create Lesson with Files - Simplified API
+
+## 📝 Create Lesson (One Request)
+
+### POST `/instructor/courses/:courseId/chapters/:chapterId/lessons`
+
+สร้าง lesson พร้อม video และ attachments ในครั้งเดียว
+
+---
+
+## Request Examples
+
+### 1. Text Lesson (No Files)
+
+```http
+POST /api/instructor/courses/1/chapters/1/lessons
+Authorization: Bearer <token>
+Content-Type: application/json
+
+{
+  "title": {
+    "th": "บทที่ 1: แนะนำ",
+    "en": "Lesson 1: Introduction"
+  },
+  "content": {
+    "th": "<p>เนื้อหาบทเรียน...</p>",
+    "en": "<p>Lesson content...</p>"
+  },
+  "type": "text",
+  "sort_order": 1,
+  "is_sequential": true
+}
+```
+
+---
+
+### 2. Video Lesson (Video Only)
+
+```http
+POST /api/instructor/courses/1/chapters/1/lessons
+Authorization: Bearer <token>
+Content-Type: multipart/form-data
+
+title_th: "บทที่ 1: แนะนำ Python"
+title_en: "Lesson 1: Introduction to Python"
+content_th: "<p>Python เป็นภาษา...</p>"
+content_en: "<p>Python is a...</p>"
+type: "video"
+sort_order: 1
+video: <lesson-video.mp4>
+```
+
+**Response 201**:
+```json
+{
+  "id": 1,
+  "chapter_id": 1,
+  "title": {
+    "th": "บทที่ 1: แนะนำ Python",
+    "en": "Lesson 1: Introduction to Python"
+  },
+  "type": "video",
+  "video": {
+    "url": "https://cdn.example.com/videos/lesson-1.m3u8",
+    "duration": "00:15:30",
+    "file_size": 52428800
+  },
+  "attachments": [],
+  "created_at": "2024-12-23T15:00:00Z"
+}
+```
+
+---
+
+### 3. Video + Attachments (Complete)
+
+```http
+POST /api/instructor/courses/1/chapters/1/lessons
+Authorization: Bearer <token>
+Content-Type: multipart/form-data
+
+# Lesson Info
+title_th: "บทที่ 1: แนะนำ Python"
+title_en: "Lesson 1: Introduction to Python"
+content_th: "<p>Python เป็นภาษา...</p>"
+content_en: "<p>Python is a...</p>"
+type: "video"
+sort_order: 1
+is_sequential: true
+
+# Video
+video: <lesson-video.mp4>
+
+# Attachments
+attachments[]: <slides.pdf>
+attachments[]: <code.zip>
+attachments[]: <exercises.docx>
+
+# Attachment Descriptions
+descriptions[0][th]: "สไลด์ประกอบการสอน"
+descriptions[0][en]: "Lecture slides"
+descriptions[1][th]: "โค้ดตัวอย่าง"
+descriptions[1][en]: "Sample code"
+descriptions[2][th]: "แบบฝึกหัด"
+descriptions[2][en]: "Exercises"
+```
+
+**Response 201**:
+```json
+{
+  "id": 1,
+  "chapter_id": 1,
+  "title": {
+    "th": "บทที่ 1: แนะนำ Python",
+    "en": "Lesson 1: Introduction to Python"
+  },
+  "content": {
+    "th": "<p>Python เป็นภาษา...</p>",
+    "en": "<p>Python is a...</p>"
+  },
+  "type": "video",
+  "sort_order": 1,
+  "is_sequential": true,
+  
+  "video": {
+    "url": "https://cdn.example.com/videos/lesson-1.m3u8",
+    "duration": "00:15:30",
+    "file_size": 52428800,
+    "uploaded_at": "2024-12-23T15:00:00Z"
+  },
+  
+  "attachments": [
+    {
+      "id": 1,
+      "file_name": "slides.pdf",
+      "file_size": 2048576,
+      "mime_type": "application/pdf",
+      "description": {
+        "th": "สไลด์ประกอบการสอน",
+        "en": "Lecture slides"
+      },
+      "sort_order": 1,
+      "download_url": "/api/lessons/1/attachments/1/download"
+    },
+    {
+      "id": 2,
+      "file_name": "code.zip",
+      "file_size": 512000,
+      "mime_type": "application/zip",
+      "description": {
+        "th": "โค้ดตัวอย่าง",
+        "en": "Sample code"
+      },
+      "sort_order": 2,
+      "download_url": "/api/lessons/1/attachments/2/download"
+    },
+    {
+      "id": 3,
+      "file_name": "exercises.docx",
+      "file_size": 256000,
+      "mime_type": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+      "description": {
+        "th": "แบบฝึกหัด",
+        "en": "Exercises"
+      },
+      "sort_order": 3,
+      "download_url": "/api/lessons/1/attachments/3/download"
+    }
+  ],
+  
+  "created_at": "2024-12-23T15:00:00Z"
+}
+```
+
+---
+
+### 4. PDF Lesson (Attachments Only)
+
+```http
+POST /api/instructor/courses/1/chapters/1/lessons
+Authorization: Bearer <token>
+Content-Type: multipart/form-data
+
+title_th: "บทที่ 2: เอกสารประกอบ"
+title_en: "Lesson 2: Reading Materials"
+type: "pdf"
+sort_order: 2
+
+attachments[]: <main-document.pdf>
+attachments[]: <supplementary.pdf>
+
+descriptions[0][th]: "เอกสารหลัก"
+descriptions[0][en]: "Main document"
+descriptions[1][th]: "เอกสารเพิ่มเติม"
+descriptions[1][en]: "Supplementary material"
+```
+
+---
+
+## Add More Files Later
+
+ถ้าต้องการเพิ่มไฟล์ทีหลัง:
+
+### POST `/instructor/courses/:courseId/lessons/:lessonId/attachments`
+
+```http
+POST /api/instructor/courses/1/lessons/1/attachments
+Authorization: Bearer <token>
+Content-Type: multipart/form-data
+
+attachments[]: <additional-file.pdf>
+descriptions[0][th]: "ไฟล์เพิ่มเติม"
+descriptions[0][en]: "Additional file"
+```
+
+---
+
+## Frontend Example
+
+```javascript
+async function createLesson(courseId, chapterId, lessonData) {
+  const formData = new FormData();
+  
+  // Basic info
+  formData.append('title_th', lessonData.title.th);
+  formData.append('title_en', lessonData.title.en);
+  formData.append('content_th', lessonData.content.th);
+  formData.append('content_en', lessonData.content.en);
+  formData.append('type', lessonData.type);
+  formData.append('sort_order', lessonData.sortOrder);
+  
+  // Video (if exists)
+  if (lessonData.video) {
+    formData.append('video', lessonData.video);
+  }
+  
+  // Attachments (if exists)
+  if (lessonData.attachments && lessonData.attachments.length > 0) {
+    lessonData.attachments.forEach((file, index) => {
+      formData.append('attachments[]', file.file);
+      formData.append(`descriptions[${index}][th]`, file.description.th);
+      formData.append(`descriptions[${index}][en]`, file.description.en);
+    });
+  }
+  
+  const response = await fetch(
+    `/api/instructor/courses/${courseId}/chapters/${chapterId}/lessons`,
+    {
+      method: 'POST',
+      headers: {
+        'Authorization': `Bearer ${token}`
+      },
+      body: formData
+    }
+  );
+  
+  return await response.json();
+}
+
+// Usage
+const lesson = await createLesson(1, 1, {
+  title: {
+    th: 'บทที่ 1: แนะนำ',
+    en: 'Lesson 1: Introduction'
+  },
+  content: {
+    th: '<p>เนื้อหา...</p>',
+    en: '<p>Content...</p>'
+  },
+  type: 'video',
+  sortOrder: 1,
+  video: videoFile,
+  attachments: [
+    {
+      file: pdfFile,
+      description: { th: 'สไลด์', en: 'Slides' }
+    },
+    {
+      file: zipFile,
+      description: { th: 'โค้ด', en: 'Code' }
+    }
+  ]
+});
+```
+
+---
+
+## Benefits
+
+✅ **One Request** - ส่งครั้งเดียว ไม่ต้องส่งหลายรอบ  
+✅ **Atomic** - สร้างสำเร็จหรือ fail ทั้งหมด  
+✅ **Faster** - ลด HTTP requests  
+✅ **Better UX** - Instructor ไม่ต้องรอหลายขั้นตอน  
+✅ **Flexible** - เพิ่มไฟล์ทีหลังได้
+
+---
+
+## Summary
+
+**Before**: 3 requests
+1. Create lesson
+2. Upload video
+3. Upload attachments
+
+**After**: 1 request
+1. Create lesson with everything ✨
diff --git a/docs/api-docs/api_prerequisites_examples.md b/docs/api-docs/api_prerequisites_examples.md
new file mode 100644
index 00000000..b32ce406
--- /dev/null
+++ b/docs/api-docs/api_prerequisites_examples.md
@@ -0,0 +1,438 @@
+# API Usage Examples - Lesson Prerequisites
+
+## New Endpoints Usage Examples
+
+---
+
+## 1. Check Lesson Access (Student)
+
+### GET `/students/courses/:courseId/lessons/:lessonId/access-check`
+
+**Purpose**: ตรวจสอบว่าสามารถเข้าถึง lesson ได้หรือไม่ โดยไม่ต้อง load content
+
+#### Request:
+```http
+GET /api/students/courses/1/lessons/3/access-check
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 200 (Can Access):
+```json
+{
+  "can_access": true,
+  "lesson": {
+    "id": 3,
+    "title": "แบบทดสอบท้ายบท",
+    "type": "quiz",
+    "sort_order": 3
+  }
+}
+```
+
+#### Response 200 (Locked - Incomplete Prerequisites):
+```json
+{
+  "can_access": false,
+  "reason": "incomplete_prerequisites",
+  "message": "กรุณาเรียนบทเรียนก่อนหน้าให้เสร็จก่อน",
+  "required_lessons": [
+    {
+      "id": 1,
+      "title": "บทที่ 1: แนะนำ",
+      "type": "video",
+      "is_completed": true
+    },
+    {
+      "id": 2,
+      "title": "บทที่ 2: ตัวแปร",
+      "type": "video",
+      "is_completed": false
+    }
+  ],
+  "missing_lessons": [2],
+  "next_available_lesson": {
+    "id": 2,
+    "title": "บทที่ 2: ตัวแปร"
+  }
+}
+```
+
+#### Response 200 (Locked - Quiz Not Passed):
+```json
+{
+  "can_access": false,
+  "reason": "quiz_not_passed",
+  "message": "กรุณาทำแบบทดสอบให้ผ่านก่อน",
+  "required_quiz": {
+    "lesson_id": 3,
+    "title": "แบบทดสอบท้ายบท",
+    "passing_score": 70,
+    "your_best_score": 55,
+    "attempts_used": 2,
+    "max_attempts": 3
+  }
+}
+```
+
+---
+
+## 2. Get Learning Page with Lock Status (Student)
+
+### GET `/students/courses/:courseId/learn`
+
+**Changes**: เพิ่ม `is_locked` และ `lock_reason` ในแต่ละ lesson
+
+#### Request:
+```http
+GET /api/students/courses/1/learn
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 200:
+```json
+{
+  "course": {
+    "id": 1,
+    "title": "Python สำหรับผู้เริ่มต้น"
+  },
+  "enrollment": {
+    "status": "enrolled",
+    "progress_percentage": 35
+  },
+  "chapters": [
+    {
+      "id": 1,
+      "title": "บทที่ 1: พื้นฐาน",
+      "sort_order": 1,
+      "lessons": [
+        {
+          "id": 1,
+          "title": "1.1 แนะนำ Python",
+          "type": "video",
+          "duration": "00:15:30",
+          "is_completed": true,
+          "is_locked": false,
+          "completed_at": "2024-12-23T10:00:00Z"
+        },
+        {
+          "id": 2,
+          "title": "1.2 ตัวแปร",
+          "type": "video",
+          "duration": "00:20:00",
+          "is_completed": false,
+          "is_locked": false
+        },
+        {
+          "id": 3,
+          "title": "1.3 แบบทดสอบ",
+          "type": "quiz",
+          "is_completed": false,
+          "is_locked": true,
+          "lock_reason": "incomplete_prerequisites",
+          "required_lessons": [1, 2]
+        },
+        {
+          "id": 4,
+          "title": "1.4 ขั้นสูง",
+          "type": "video",
+          "duration": "00:25:00",
+          "is_completed": false,
+          "is_locked": true,
+          "lock_reason": "quiz_not_passed",
+          "required_quiz": 3
+        }
+      ]
+    }
+  ]
+}
+```
+
+---
+
+## 3. Get Lesson Content with Prerequisites Check (Student)
+
+### GET `/students/courses/:courseId/lessons/:lessonId`
+
+**Changes**: ตรวจสอบ prerequisites ก่อน return content
+
+#### Request:
+```http
+GET /api/students/courses/1/lessons/3
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 403 (Locked):
+```json
+{
+  "error": {
+    "code": "LESSON_LOCKED",
+    "message": "Cannot access this lesson",
+    "reason": "incomplete_prerequisites",
+    "required_lessons": [1, 2],
+    "completed_lessons": [1],
+    "missing_lessons": [2],
+    "next_available_lesson": {
+      "id": 2,
+      "title": "บทที่ 2: ตัวแปร",
+      "type": "video"
+    }
+  }
+}
+```
+
+---
+
+## 4. Create Lesson with Prerequisites (Instructor)
+
+### POST `/instructor/courses/:courseId/chapters/:chapterId/lessons`
+
+**Changes**: เพิ่ม fields สำหรับ prerequisites
+
+#### Request:
+```http
+POST /api/instructor/courses/1/chapters/1/lessons
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+Content-Type: application/json
+
+{
+  "title": {
+    "th": "แบบทดสอบท้ายบท",
+    "en": "Chapter Quiz"
+  },
+  "content": {
+    "th": "<p>ทดสอบความเข้าใจ</p>",
+    "en": "<p>Test your understanding</p>"
+  },
+  "type": "quiz",
+  "sort_order": 3,
+  "is_sequential": true,
+  "prerequisite_lesson_ids": [1, 2],
+  "require_pass_quiz": true
+}
+```
+
+#### Response 201:
+```json
+{
+  "id": 3,
+  "chapter_id": 1,
+  "title": {
+    "th": "แบบทดสอบท้ายบท",
+    "en": "Chapter Quiz"
+  },
+  "type": "quiz",
+  "sort_order": 3,
+  "is_sequential": true,
+  "prerequisite_lesson_ids": [1, 2],
+  "require_pass_quiz": true,
+  "created_at": "2024-12-23T14:00:00Z"
+}
+```
+
+#### Response 422 (Validation Error):
+```json
+{
+  "error": {
+    "code": "VALIDATION_ERROR",
+    "message": "Invalid prerequisites",
+    "details": [
+      {
+        "field": "prerequisite_lesson_ids",
+        "message": "Lesson ID 99 does not exist"
+      }
+    ]
+  }
+}
+```
+
+---
+
+## 5. View Lesson Prerequisites (Instructor)
+
+### GET `/instructor/courses/:courseId/lessons/:lessonId/prerequisites`
+
+#### Request:
+```http
+GET /api/instructor/courses/1/lessons/4/prerequisites
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+```
+
+#### Response 200:
+```json
+{
+  "lesson": {
+    "id": 4,
+    "title": "บทที่ 3: ขั้นสูง",
+    "type": "video",
+    "sort_order": 4
+  },
+  "is_sequential": true,
+  "prerequisites": [
+    {
+      "id": 3,
+      "title": "แบบทดสอบท้ายบท",
+      "type": "quiz",
+      "require_pass": true,
+      "passing_score": 70
+    }
+  ],
+  "affected_students": {
+    "total_enrolled": 150,
+    "can_access": 85,
+    "locked": 65,
+    "breakdown": {
+      "incomplete_prerequisites": 45,
+      "quiz_not_passed": 20
+    }
+  }
+}
+```
+
+---
+
+## 6. Update Lesson Prerequisites (Instructor)
+
+### POST `/instructor/courses/:courseId/lessons/:lessonId/prerequisites`
+
+#### Request:
+```http
+POST /api/instructor/courses/1/lessons/4/prerequisites
+Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
+Content-Type: application/json
+
+{
+  "is_sequential": true,
+  "prerequisite_lesson_ids": [3],
+  "require_pass_quiz": false
+}
+```
+
+#### Response 200:
+```json
+{
+  "lesson_id": 4,
+  "is_sequential": true,
+  "prerequisites": [
+    {
+      "id": 3,
+      "title": "แบบทดสอบท้ายบท",
+      "type": "quiz",
+      "require_pass": false
+    }
+  ],
+  "message": "Prerequisites updated successfully",
+  "affected_students": {
+    "newly_unlocked": 20,
+    "still_locked": 45
+  }
+}
+```
+
+---
+
+## Error Codes
+
+### New Error Codes for Prerequisites
+
+| Code | Description |
+|------|-------------|
+| `LESSON_LOCKED` | Cannot access lesson due to prerequisites |
+| `INCOMPLETE_PREREQUISITES` | Required lessons not completed |
+| `QUIZ_NOT_PASSED` | Required quiz not passed |
+| `INVALID_PREREQUISITES` | Invalid prerequisite configuration |
+| `CIRCULAR_DEPENDENCY` | Circular dependency detected |
+
+---
+
+## Frontend Integration Examples
+
+### 1. Display Locked Lesson
+
+```javascript
+function LessonItem({ lesson }) {
+  if (lesson.is_locked) {
+    return (
+      <div className="lesson-item locked">
+        <LockIcon />
+        <span className="lesson-title">{lesson.title}</span>
+        
+        {lesson.lock_reason === 'incomplete_prerequisites' && (
+          <Tooltip>
+            กรุณาเรียนบทเรียนก่อนหน้าให้เสร็จก่อน
+            <ul>
+              {lesson.required_lessons.map(id => (
+                <li key={id}>Lesson {id}</li>
+              ))}
+            </ul>
+          </Tooltip>
+        )}
+        
+        {lesson.lock_reason === 'quiz_not_passed' && (
+          <Tooltip>
+            กรุณาทำแบบทดสอบให้ผ่านก่อน (ต้องได้ 70% ขึ้นไป)
+          </Tooltip>
+        )}
+      </div>
+    );
+  }
+  
+  return (
+    <Link to={`/lessons/${lesson.id}`} className="lesson-item">
+      {lesson.is_completed ? <CheckIcon /> : <PlayIcon />}
+      <span>{lesson.title}</span>
+    </Link>
+  );
+}
+```
+
+### 2. Check Access Before Navigation
+
+```javascript
+async function navigateToLesson(courseId, lessonId) {
+  try {
+    const response = await fetch(
+      `/api/students/courses/${courseId}/lessons/${lessonId}/access-check`,
+      {
+        headers: {
+          'Authorization': `Bearer ${token}`
+        }
+      }
+    );
+    
+    const data = await response.json();
+    
+    if (data.can_access) {
+      // Navigate to lesson
+      router.push(`/courses/${courseId}/lessons/${lessonId}`);
+    } else {
+      // Show lock message
+      if (data.reason === 'incomplete_prerequisites') {
+        showAlert(`กรุณาเรียนบทเรียนก่อนหน้าให้เสร็จก่อน`);
+        // Highlight next available lesson
+        highlightLesson(data.next_available_lesson.id);
+      } else if (data.reason === 'quiz_not_passed') {
+        showAlert(`กรุณาทำแบบทดสอบให้ผ่านก่อน`);
+        // Navigate to quiz
+        router.push(`/courses/${courseId}/lessons/${data.required_quiz.lesson_id}`);
+      }
+    }
+  } catch (error) {
+    console.error('Error checking lesson access:', error);
+  }
+}
+```
+
+---
+
+## Summary
+
+**New Endpoints**: 3
+- `GET /students/courses/:courseId/lessons/:lessonId/access-check`
+- `GET /instructor/courses/:courseId/lessons/:lessonId/prerequisites`
+- `POST /instructor/courses/:courseId/lessons/:lessonId/prerequisites`
+
+**Modified Endpoints**: 4
+- `GET /students/courses/:courseId/learn` - เพิ่ม lock status
+- `GET /students/courses/:courseId/lessons/:lessonId` - เช็ค prerequisites
+- `POST /instructor/courses/:courseId/chapters/:chapterId/lessons` - รองรับ prerequisites
+- `PUT /instructor/courses/:courseId/lessons/:lessonId` - รองรับ prerequisites
diff --git a/docs/api_usage_examples.md b/docs/api-docs/api_usage_examples.md
similarity index 100%
rename from docs/api_usage_examples.md
rename to docs/api-docs/api_usage_examples.md
diff --git a/docs/development_setup.md b/docs/development_setup.md
new file mode 100644
index 00000000..34ff79bc
--- /dev/null
+++ b/docs/development_setup.md
@@ -0,0 +1,650 @@
+# Development Environment Setup Guide
+
+## 🏗️ Architecture Overview
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                    Developer Machines                        │
+│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐      │
+│  │  Frontend    │  │  Frontend    │  │   Backend    │      │
+│  │  (Student)   │  │  (Admin)     │  │   (API)      │      │
+│  │  Port: 3000  │  │  Port: 3001  │  │  Port: 4000  │      │
+│  └──────┬───────┘  └──────┬───────┘  └──────┬───────┘      │
+│         │                  │                  │              │
+│         └──────────────────┴──────────────────┘              │
+│                            │                                 │
+└────────────────────────────┼─────────────────────────────────┘
+                             │
+                             ▼
+┌─────────────────────────────────────────────────────────────┐
+│              Proxmox Server (Shared Services)                │
+│                                                              │
+│  ┌──────────────────────────────────────────────────────┐  │
+│  │              Docker Compose Stack                     │  │
+│  │                                                        │  │
+│  │  ┌────────────┐  ┌────────────┐  ┌────────────┐     │  │
+│  │  │ PostgreSQL │  │   MinIO    │  │   Redis    │     │  │
+│  │  │ Port: 5432 │  │ Port: 9000 │  │ Port: 6379 │     │  │
+│  │  └────────────┘  └────────────┘  └────────────┘     │  │
+│  │                                                        │  │
+│  │  ┌────────────┐  ┌────────────┐  ┌────────────┐     │  │
+│  │  │  Mailhog   │  │   Adminer  │  │  Forgejo   │     │  │
+│  │  │ Port: 1025 │  │ Port: 8080 │  │ Port: 3030 │     │  │
+│  │  │ Port: 8025 │  │            │  │ Port: 2222 │     │  │
+│  │  └────────────┘  └────────────┘  └────────────┘     │  │
+│  └──────────────────────────────────────────────────────┘  │
+│                                                              │
+│  IP: 192.168.1.100 (example)                                │
+└─────────────────────────────────────────────────────────────┘
+```
+
+---
+
+## 📦 Services on Proxmox Server
+
+### 1. PostgreSQL - Database
+- **Port**: 5432
+- **Purpose**: Main application database
+- **Access**: All developers
+
+### 2. MinIO - S3-compatible Storage
+- **Port**: 9000 (API), 9001 (Console)
+- **Purpose**: File storage (videos, documents, images)
+- **Access**: Backend + Developers
+
+### 3. Redis - Cache & Session
+- **Port**: 6379
+- **Purpose**: Caching, session storage, queue
+- **Access**: Backend only
+
+### 4. Mailhog - Email Testing
+- **Port**: 1025 (SMTP), 8025 (Web UI)
+- **Purpose**: Catch all emails in development
+- **Access**: All developers
+
+### 5. Adminer - Database Management
+- **Port**: 8080
+- **Purpose**: Web-based database management
+- **Access**: All developers
+
+### 6. Forgejo - Git Server
+- **Port**: 3030 (HTTP), 2222 (SSH)
+- **Purpose**: Self-hosted Git repository (like GitHub/GitLab)
+- **Access**: All developers
+
+---
+
+## 🐳 Docker Compose Configuration
+
+Create this file on your Proxmox server:
+
+### `/opt/elearning-dev/docker-compose.yml`
+
+```yaml
+version: '3.8'
+
+services:
+  # PostgreSQL Database
+  postgres:
+    image: postgres:16-alpine
+    container_name: elearning-postgres
+    restart: unless-stopped
+    ports:
+      - "5432:5432"
+    environment:
+      POSTGRES_DB: elearning_dev
+      POSTGRES_USER: elearning
+      POSTGRES_PASSWORD: dev_password_change_in_prod
+      POSTGRES_INITDB_ARGS: "--encoding=UTF8 --locale=en_US.UTF-8"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+      - ./init-scripts:/docker-entrypoint-initdb.d
+    networks:
+      - elearning-network
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U elearning"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  # MinIO - S3 Compatible Storage
+  minio:
+    image: minio/minio:latest
+    container_name: elearning-minio
+    restart: unless-stopped
+    ports:
+      - "9000:9000"  # API
+      - "9001:9001"  # Console
+    environment:
+      MINIO_ROOT_USER: minioadmin
+      MINIO_ROOT_PASSWORD: minioadmin123
+      MINIO_BROWSER_REDIRECT_URL: http://192.168.1.100:9001
+    volumes:
+      - minio_data:/data
+    command: server /data --console-address ":9001"
+    networks:
+      - elearning-network
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:9000/minio/health/live"]
+      interval: 30s
+      timeout: 20s
+      retries: 3
+
+  # MinIO Client - Create buckets on startup
+  minio-init:
+    image: minio/mc:latest
+    container_name: elearning-minio-init
+    depends_on:
+      - minio
+    entrypoint: >
+      /bin/sh -c "
+      sleep 5;
+      /usr/bin/mc alias set myminio http://minio:9000 minioadmin minioadmin123;
+      /usr/bin/mc mb myminio/courses --ignore-existing;
+      /usr/bin/mc mb myminio/videos --ignore-existing;
+      /usr/bin/mc mb myminio/documents --ignore-existing;
+      /usr/bin/mc mb myminio/images --ignore-existing;
+      /usr/bin/mc mb myminio/attachments --ignore-existing;
+      /usr/bin/mc anonymous set download myminio/images;
+      echo 'MinIO buckets created successfully';
+      exit 0;
+      "
+    networks:
+      - elearning-network
+
+  # Redis - Cache & Session Store
+  redis:
+    image: redis:7-alpine
+    container_name: elearning-redis
+    restart: unless-stopped
+    ports:
+      - "6379:6379"
+    command: redis-server --appendonly yes --requirepass dev_redis_password
+    volumes:
+      - redis_data:/data
+    networks:
+      - elearning-network
+    healthcheck:
+      test: ["CMD", "redis-cli", "--raw", "incr", "ping"]
+      interval: 10s
+      timeout: 3s
+      retries: 5
+
+  # Mailhog - Email Testing
+  mailhog:
+    image: mailhog/mailhog:latest
+    container_name: elearning-mailhog
+    restart: unless-stopped
+    ports:
+      - "1025:1025"  # SMTP
+      - "8025:8025"  # Web UI
+    networks:
+      - elearning-network
+
+  # Adminer - Database Management UI
+  adminer:
+    image: adminer:latest
+    container_name: elearning-adminer
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    environment:
+      ADMINER_DEFAULT_SERVER: postgres
+      ADMINER_DESIGN: dracula
+    networks:
+      - elearning-network
+    depends_on:
+      - postgres
+
+  # Forgejo - Self-hosted Git Server
+  forgejo:
+    image: codeberg.org/forgejo/forgejo:1.21
+    container_name: elearning-forgejo
+    restart: unless-stopped
+    ports:
+      - "3030:3000"  # HTTP
+      - "2222:22"    # SSH
+    environment:
+      - USER_UID=1000
+      - USER_GID=1000
+      - FORGEJO__database__DB_TYPE=postgres
+      - FORGEJO__database__HOST=postgres:5432
+      - FORGEJO__database__NAME=forgejo
+      - FORGEJO__database__USER=elearning
+      - FORGEJO__database__PASSWD=dev_password_change_in_prod
+    volumes:
+      - forgejo_data:/data
+      - /etc/timezone:/etc/timezone:ro
+      - /etc/localtime:/etc/localtime:ro
+    networks:
+      - elearning-network
+    depends_on:
+      - postgres
+
+volumes:
+  postgres_data:
+    driver: local
+  minio_data:
+    driver: local
+  redis_data:
+    driver: local
+  forgejo_data:
+    driver: local
+
+networks:
+  elearning-network:
+    driver: bridge
+```
+
+---
+
+## 🚀 Setup Instructions
+
+### Step 1: Prepare Proxmox Server
+
+```bash
+# SSH to Proxmox server
+ssh root@192.168.1.100
+
+# Create directory
+mkdir -p /opt/elearning-dev
+cd /opt/elearning-dev
+
+# Create docker-compose.yml (paste content above)
+nano docker-compose.yml
+
+# Create init scripts directory
+mkdir init-scripts
+```
+
+### Step 2: Create Database Init Script (Optional)
+
+Create `/opt/elearning-dev/init-scripts/01-create-extensions.sql`:
+
+```sql
+-- Enable required PostgreSQL extensions
+CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
+CREATE EXTENSION IF NOT EXISTS "pg_trgm";
+
+-- Create Forgejo database
+CREATE DATABASE forgejo;
+GRANT ALL PRIVILEGES ON DATABASE forgejo TO elearning;
+
+-- Create additional schemas if needed
+-- CREATE SCHEMA IF NOT EXISTS analytics;
+```
+
+### Step 3: Start Services
+
+```bash
+# Start all services
+docker-compose up -d
+
+# Check status
+docker-compose ps
+
+# View logs
+docker-compose logs -f
+
+# Check specific service
+docker-compose logs -f postgres
+```
+
+### Step 4: Verify Services
+
+```bash
+# Test PostgreSQL
+docker exec -it elearning-postgres psql -U elearning -d elearning_dev -c "SELECT version();"
+
+# Test Redis
+docker exec -it elearning-redis redis-cli -a dev_redis_password ping
+
+# Test MinIO
+curl http://192.168.1.100:9000/minio/health/live
+```
+
+---
+
+## 💻 Developer Machine Setup
+
+### Frontend (Student) - Port 3000
+
+**Directory**: `/path/to/frontend-student`
+
+**`.env.local`**:
+```env
+# API Configuration
+NEXT_PUBLIC_API_URL=http://localhost:4000/api
+NEXT_PUBLIC_WS_URL=ws://localhost:4000
+
+# MinIO/S3 Configuration
+NEXT_PUBLIC_S3_ENDPOINT=http://192.168.1.100:9000
+NEXT_PUBLIC_S3_BUCKET=courses
+
+# App Configuration
+NEXT_PUBLIC_APP_NAME=E-Learning Platform
+NEXT_PUBLIC_APP_URL=http://localhost:3000
+```
+
+**Start Command**:
+```bash
+npm run dev
+# or
+yarn dev
+```
+
+---
+
+### Frontend (Admin) - Port 3001
+
+**Directory**: `/path/to/frontend-admin`
+
+**`.env.local`**:
+```env
+# API Configuration
+NEXT_PUBLIC_API_URL=http://localhost:4000/api
+NEXT_PUBLIC_WS_URL=ws://localhost:4000
+
+# MinIO/S3 Configuration
+NEXT_PUBLIC_S3_ENDPOINT=http://192.168.1.100:9000
+NEXT_PUBLIC_S3_BUCKET=courses
+
+# App Configuration
+NEXT_PUBLIC_APP_NAME=E-Learning Admin
+NEXT_PUBLIC_APP_URL=http://localhost:3001
+```
+
+**package.json** (modify dev script):
+```json
+{
+  "scripts": {
+    "dev": "next dev -p 3001"
+  }
+}
+```
+
+**Start Command**:
+```bash
+npm run dev
+# or
+yarn dev
+```
+
+---
+
+### Backend (API) - Port 4000
+
+**Directory**: `/path/to/backend`
+
+**`.env`**:
+```env
+# Application
+NODE_ENV=development
+PORT=4000
+APP_URL=http://localhost:4000
+
+# Database
+DATABASE_URL=postgresql://elearning:dev_password_change_in_prod@192.168.1.100:5432/elearning_dev
+DB_HOST=192.168.1.100
+DB_PORT=5432
+DB_NAME=elearning_dev
+DB_USER=elearning
+DB_PASSWORD=dev_password_change_in_prod
+
+# Redis
+REDIS_URL=redis://:dev_redis_password@192.168.1.100:6379
+REDIS_HOST=192.168.1.100
+REDIS_PORT=6379
+REDIS_PASSWORD=dev_redis_password
+
+# MinIO/S3
+S3_ENDPOINT=http://192.168.1.100:9000
+S3_ACCESS_KEY=minioadmin
+S3_SECRET_KEY=minioadmin123
+S3_BUCKET_COURSES=courses
+S3_BUCKET_VIDEOS=videos
+S3_BUCKET_DOCUMENTS=documents
+S3_BUCKET_IMAGES=images
+S3_BUCKET_ATTACHMENTS=attachments
+S3_REGION=us-east-1
+S3_USE_SSL=false
+
+# Email (Mailhog)
+SMTP_HOST=192.168.1.100
+SMTP_PORT=1025
+SMTP_USER=
+SMTP_PASSWORD=
+SMTP_FROM=noreply@elearning.local
+SMTP_FROM_NAME=E-Learning Platform
+
+# JWT
+JWT_SECRET=your-super-secret-jwt-key-change-in-production
+JWT_EXPIRES_IN=24h
+JWT_REFRESH_EXPIRES_IN=7d
+
+# CORS
+CORS_ORIGIN=http://localhost:3000,http://localhost:3001
+
+# File Upload
+MAX_FILE_SIZE=104857600  # 100MB
+ALLOWED_VIDEO_TYPES=video/mp4,video/webm
+ALLOWED_DOCUMENT_TYPES=application/pdf,application/msword,application/vnd.openxmlformats-officedocument.wordprocessingml.document
+ALLOWED_IMAGE_TYPES=image/jpeg,image/png,image/gif
+```
+
+**Start Command**:
+```bash
+npm run dev
+# or
+yarn dev
+```
+
+---
+
+## 🔧 Useful Commands
+
+### Docker Management
+
+```bash
+# Stop all services
+docker-compose down
+
+# Stop and remove volumes (⚠️ deletes data)
+docker-compose down -v
+
+# Restart specific service
+docker-compose restart postgres
+
+# View logs
+docker-compose logs -f postgres
+
+# Execute command in container
+docker exec -it elearning-postgres psql -U elearning -d elearning_dev
+```
+
+### Database Management
+
+```bash
+# Backup database
+docker exec elearning-postgres pg_dump -U elearning elearning_dev > backup.sql
+
+# Restore database
+cat backup.sql | docker exec -i elearning-postgres psql -U elearning -d elearning_dev
+
+# Access database shell
+docker exec -it elearning-postgres psql -U elearning -d elearning_dev
+```
+
+### MinIO Management
+
+```bash
+# Access MinIO Console
+# Open browser: http://192.168.1.100:9001
+# Username: minioadmin
+# Password: minioadmin123
+
+# Using MinIO Client (mc)
+docker exec -it elearning-minio mc alias set local http://localhost:9000 minioadmin minioadmin123
+docker exec -it elearning-minio mc ls local/
+```
+
+---
+
+## 🌐 Access URLs
+
+| Service | URL | Credentials |
+|---------|-----|-------------|
+| **Frontend (Student)** | http://localhost:3000 | - |
+| **Frontend (Admin)** | http://localhost:3001 | - |
+| **Backend API** | http://localhost:4000 | - |
+| **PostgreSQL** | 192.168.1.100:5432 | elearning / dev_password_change_in_prod |
+| **MinIO Console** | http://192.168.1.100:9001 | minioadmin / minioadmin123 |
+| **MinIO API** | http://192.168.1.100:9000 | - |
+| **Redis** | 192.168.1.100:6379 | Password: dev_redis_password |
+| **Mailhog UI** | http://192.168.1.100:8025 | - |
+| **Adminer** | http://192.168.1.100:8080 | - |
+| **Forgejo** | http://192.168.1.100:3030 | Setup on first visit |
+| **Forgejo SSH** | ssh://git@192.168.1.100:2222 | SSH key required |
+
+---
+
+## 📊 Resource Requirements
+
+### Proxmox Server (Recommended)
+- **CPU**: 4 cores
+- **RAM**: 8 GB
+- **Storage**: 50 GB (SSD recommended)
+- **Network**: 1 Gbps
+
+### Developer Machines
+- **CPU**: 2+ cores
+- **RAM**: 8 GB
+- **Storage**: 20 GB free space
+
+---
+
+## 🔒 Security Notes
+
+> [!WARNING]
+> **Development Environment Only!**
+> - These credentials are for development only
+> - Change all passwords in production
+> - Never commit `.env` files to git
+> - Use `.env.example` for templates
+
+---
+
+## 🐛 Troubleshooting
+
+### Cannot connect to PostgreSQL
+
+```bash
+# Check if container is running
+docker ps | grep postgres
+
+# Check logs
+docker logs elearning-postgres
+
+# Test connection
+docker exec -it elearning-postgres pg_isready -U elearning
+```
+
+### Cannot connect to MinIO
+
+```bash
+# Check if container is running
+docker ps | grep minio
+
+# Check logs
+docker logs elearning-minio
+
+# Test health
+curl http://192.168.1.100:9000/minio/health/live
+```
+
+### Port already in use
+
+```bash
+# Find process using port
+lsof -i :5432
+# or
+netstat -tulpn | grep 5432
+
+# Kill process
+kill -9 <PID>
+```
+
+### Docker network issues
+
+```bash
+# Recreate network
+docker-compose down
+docker network prune
+docker-compose up -d
+```
+
+---
+
+## 📝 Development Workflow
+
+### Daily Workflow
+
+1. **Start Proxmox Services** (if not running)
+   ```bash
+   ssh root@192.168.1.100
+   cd /opt/elearning-dev
+   docker-compose up -d
+   ```
+
+2. **Start Backend**
+   ```bash
+   cd /path/to/backend
+   npm run dev
+   ```
+
+3. **Start Frontend (Student)**
+   ```bash
+   cd /path/to/frontend-student
+   npm run dev
+   ```
+
+4. **Start Frontend (Admin)**
+   ```bash
+   cd /path/to/frontend-admin
+   npm run dev
+   ```
+
+5. **Develop & Test**
+   - Student app: http://localhost:3000
+   - Admin app: http://localhost:3001
+   - API: http://localhost:4000
+   - Check emails: http://192.168.1.100:8025
+
+### End of Day
+
+```bash
+# Optional: Stop services to save resources
+ssh root@192.168.1.100
+cd /opt/elearning-dev
+docker-compose stop
+```
+
+---
+
+## 🎯 Next Steps
+
+1. ✅ Setup Proxmox server with Docker Compose
+2. ✅ Configure developer machines with `.env` files
+3. ✅ Test connectivity to all services
+4. ✅ Run database migrations
+5. ✅ Seed initial data
+6. ✅ Start development!
+
+---
+
+## 📚 Additional Resources
+
+- [Docker Compose Documentation](https://docs.docker.com/compose/)
+- [PostgreSQL Documentation](https://www.postgresql.org/docs/)
+- [MinIO Documentation](https://min.io/docs/)
+- [Redis Documentation](https://redis.io/documentation)
diff --git a/docs/forgejo_setup.md b/docs/forgejo_setup.md
new file mode 100644
index 00000000..93dc35b0
--- /dev/null
+++ b/docs/forgejo_setup.md
@@ -0,0 +1,493 @@
+# Forgejo Setup Guide
+
+## 🎯 What is Forgejo?
+
+**Forgejo** is a self-hosted Git server (like GitHub or GitLab) that you can run on your own server. It's perfect for:
+- 📦 Hosting your code repositories privately
+- 👥 Team collaboration with pull requests
+- 🔍 Code review
+- 📋 Issue tracking
+- 🔄 CI/CD integration
+
+---
+
+## 🚀 Initial Setup
+
+### Step 1: Access Forgejo
+
+After starting Docker Compose, open your browser:
+
+```
+http://192.168.1.100:3030
+```
+
+You'll see the **Initial Configuration** page.
+
+---
+
+### Step 2: Configure Forgejo
+
+Fill in the following settings:
+
+#### **Database Settings** (Already configured via Docker)
+- ✅ Database Type: `PostgreSQL`
+- ✅ Host: `postgres:5432`
+- ✅ Username: `elearning`
+- ✅ Password: `dev_password_change_in_prod`
+- ✅ Database Name: `forgejo`
+
+#### **General Settings**
+- **Site Title**: `E-Learning Dev`
+- **Repository Root Path**: `/data/git/repositories` (default)
+- **Git LFS Root Path**: `/data/git/lfs` (default)
+- **Run As Username**: `git` (default)
+
+#### **Server and Third-Party Service Settings**
+- **SSH Server Domain**: `192.168.1.100`
+- **SSH Port**: `2222`
+- **Forgejo HTTP Listen Port**: `3000` (internal)
+- **Forgejo Base URL**: `http://192.168.1.100:3030`
+- **Log Path**: `/data/forgejo/log` (default)
+
+#### **Email Settings** (Optional - use Mailhog)
+- **SMTP Host**: `mailhog:1025`
+- **Send Email As**: `forgejo@elearning.local`
+- **Require Sign-In to View Pages**: ✅ (recommended)
+
+#### **Administrator Account Settings**
+Create your admin account:
+- **Username**: `admin`
+- **Password**: `admin123` (change in production!)
+- **Email**: `admin@elearning.local`
+
+Click **Install Forgejo**
+
+---
+
+## 👥 Creating Developer Accounts
+
+### Option 1: Self-Registration (if enabled)
+
+Users can register at: `http://192.168.1.100:3030/user/sign_up`
+
+### Option 2: Admin Creates Users
+
+1. Login as admin
+2. Go to **Site Administration** (top right)
+3. Click **User Accounts**
+4. Click **Create User Account**
+5. Fill in:
+   - Username
+   - Email
+   - Password
+6. Click **Create User Account**
+
+---
+
+## 📦 Creating Your First Repository
+
+### Via Web Interface
+
+1. Login to Forgejo
+2. Click **+** (top right) → **New Repository**
+3. Fill in:
+   - **Owner**: Your username
+   - **Repository Name**: `elearning-backend`
+   - **Description**: Backend API for E-Learning Platform
+   - **Visibility**: Private
+   - **Initialize Repository**: ✅ Add README
+   - **Add .gitignore**: Node
+   - **Add License**: MIT (optional)
+4. Click **Create Repository**
+
+---
+
+## 🔑 Setting Up SSH Access
+
+### Step 1: Generate SSH Key (if you don't have one)
+
+```bash
+# On your developer machine
+ssh-keygen -t ed25519 -C "your_email@example.com"
+
+# Press Enter to accept default location (~/.ssh/id_ed25519)
+# Enter a passphrase (optional but recommended)
+```
+
+### Step 2: Add SSH Key to Forgejo
+
+```bash
+# Copy your public key
+cat ~/.ssh/id_ed25519.pub
+```
+
+1. Login to Forgejo
+2. Click your **avatar** (top right) → **Settings**
+3. Click **SSH / GPG Keys**
+4. Click **Add Key**
+5. Paste your public key
+6. Give it a name (e.g., "MacBook Pro")
+7. Click **Add Key**
+
+### Step 3: Test SSH Connection
+
+```bash
+ssh -T git@192.168.1.100 -p 2222
+```
+
+You should see:
+```
+Hi there, <username>! You've successfully authenticated, but Forgejo does not provide shell access.
+```
+
+---
+
+## 💻 Using Git with Forgejo
+
+### Clone Repository
+
+```bash
+# Via SSH (recommended)
+git clone ssh://git@192.168.1.100:2222/<username>/elearning-backend.git
+
+# Via HTTP
+git clone http://192.168.1.100:3030/<username>/elearning-backend.git
+```
+
+### Push Existing Project
+
+```bash
+cd /path/to/your/project
+
+# Initialize git (if not already)
+git init
+
+# Add Forgejo as remote
+git remote add origin ssh://git@192.168.1.100:2222/<username>/elearning-backend.git
+
+# Add files
+git add .
+git commit -m "Initial commit"
+
+# Push to Forgejo
+git push -u origin main
+```
+
+---
+
+## 🏢 Organizing Repositories
+
+### Create Organization
+
+1. Click **+** (top right) → **New Organization**
+2. Fill in:
+   - **Organization Name**: `elearning-team`
+   - **Visibility**: Private
+3. Click **Create Organization**
+
+### Add Team Members
+
+1. Go to Organization → **Teams**
+2. Click **Create New Team**
+3. Fill in:
+   - **Team Name**: `Developers`
+   - **Permission**: Write
+4. Click **Create Team**
+5. Click **Add Team Member** and select users
+
+### Create Repository in Organization
+
+1. Click **+** → **New Repository**
+2. **Owner**: Select `elearning-team`
+3. Fill in repository details
+4. Click **Create Repository**
+
+---
+
+## 🔄 Recommended Repository Structure
+
+```
+elearning-team/
+├── elearning-backend          # Backend API
+├── elearning-frontend-student # Student Frontend
+├── elearning-frontend-admin   # Admin Frontend
+├── elearning-docs             # Documentation
+└── elearning-infrastructure   # Docker, CI/CD configs
+```
+
+---
+
+## 🎯 Workflow Example
+
+### 1. Clone Repository
+
+```bash
+git clone ssh://git@192.168.1.100:2222/elearning-team/elearning-backend.git
+cd elearning-backend
+```
+
+### 2. Create Feature Branch
+
+```bash
+git checkout -b feature/add-quiz-api
+```
+
+### 3. Make Changes
+
+```bash
+# Edit files
+nano src/controllers/quizController.js
+
+# Commit changes
+git add .
+git commit -m "feat: add quiz submission endpoint"
+```
+
+### 4. Push Branch
+
+```bash
+git push origin feature/add-quiz-api
+```
+
+### 5. Create Pull Request
+
+1. Go to repository in Forgejo
+2. Click **Pull Requests**
+3. Click **New Pull Request**
+4. Select:
+   - **Base**: `main`
+   - **Compare**: `feature/add-quiz-api`
+5. Fill in title and description
+6. Click **Create Pull Request**
+
+### 6. Code Review
+
+Team members can:
+- Review code changes
+- Add comments
+- Approve or request changes
+
+### 7. Merge
+
+Once approved:
+1. Click **Merge Pull Request**
+2. Select merge method (Merge / Squash / Rebase)
+3. Click **Confirm Merge**
+
+---
+
+## 🔧 Git Configuration
+
+### Set Git Config for Forgejo
+
+```bash
+# Set your identity
+git config --global user.name "Your Name"
+git config --global user.email "your.email@example.com"
+
+# Use SSH by default
+git config --global url."ssh://git@192.168.1.100:2222/".insteadOf "http://192.168.1.100:3030/"
+
+# Set default branch name
+git config --global init.defaultBranch main
+```
+
+### SSH Config (Optional)
+
+Create `~/.ssh/config`:
+
+```
+Host forgejo
+    HostName 192.168.1.100
+    Port 2222
+    User git
+    IdentityFile ~/.ssh/id_ed25519
+```
+
+Now you can clone with:
+```bash
+git clone forgejo:<username>/elearning-backend.git
+```
+
+---
+
+## 📋 Common Tasks
+
+### Create .gitignore
+
+```bash
+# Create .gitignore for Node.js
+cat > .gitignore << 'EOF'
+# Dependencies
+node_modules/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Environment variables
+.env
+.env.local
+.env.*.local
+
+# Build output
+dist/
+build/
+.next/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+logs/
+*.log
+
+# Database
+*.sqlite
+*.db
+EOF
+
+git add .gitignore
+git commit -m "chore: add .gitignore"
+git push
+```
+
+### Protect Main Branch
+
+1. Go to Repository → **Settings**
+2. Click **Branches**
+3. Click **Add Rule**
+4. Fill in:
+   - **Branch Name Pattern**: `main`
+   - **Enable Branch Protection**: ✅
+   - **Require Pull Request**: ✅
+   - **Require Approvals**: 1
+   - **Dismiss Stale Approvals**: ✅
+5. Click **Save**
+
+---
+
+## 🐛 Troubleshooting
+
+### Cannot Connect via SSH
+
+```bash
+# Check if Forgejo is running
+docker ps | grep forgejo
+
+# Test SSH connection
+ssh -T git@192.168.1.100 -p 2222 -v
+
+# Check if port 2222 is open
+telnet 192.168.1.100 2222
+```
+
+### Permission Denied (publickey)
+
+```bash
+# Make sure your SSH key is added to Forgejo
+# Check SSH agent
+ssh-add -l
+
+# Add your key to agent
+ssh-add ~/.ssh/id_ed25519
+```
+
+### Cannot Push to Repository
+
+```bash
+# Check remote URL
+git remote -v
+
+# Update remote URL
+git remote set-url origin ssh://git@192.168.1.100:2222/<username>/repo.git
+
+# Check your permissions in Forgejo
+# Make sure you have write access to the repository
+```
+
+---
+
+## 🎯 Best Practices
+
+### 1. **Use SSH for Authentication**
+- More secure than HTTP
+- No need to enter password every time
+
+### 2. **Protect Main Branch**
+- Require pull requests
+- Require code reviews
+- Prevent force pushes
+
+### 3. **Use Meaningful Commit Messages**
+```bash
+# Good
+git commit -m "feat: add user authentication endpoint"
+git commit -m "fix: resolve quiz submission bug"
+git commit -m "docs: update API documentation"
+
+# Bad
+git commit -m "update"
+git commit -m "fix bug"
+git commit -m "changes"
+```
+
+### 4. **Create Feature Branches**
+```bash
+# Feature
+git checkout -b feature/user-profile
+
+# Bug fix
+git checkout -b fix/login-error
+
+# Hotfix
+git checkout -b hotfix/security-patch
+```
+
+### 5. **Regular Commits**
+- Commit often
+- Keep commits focused
+- One logical change per commit
+
+---
+
+## 📚 Additional Resources
+
+- [Forgejo Documentation](https://forgejo.org/docs/)
+- [Git Documentation](https://git-scm.com/doc)
+- [GitHub Flow Guide](https://guides.github.com/introduction/flow/)
+
+---
+
+## ✅ Quick Reference
+
+| Action | Command |
+|--------|---------|
+| Clone repo | `git clone ssh://git@192.168.1.100:2222/<user>/<repo>.git` |
+| Create branch | `git checkout -b feature/name` |
+| Stage changes | `git add .` |
+| Commit | `git commit -m "message"` |
+| Push | `git push origin branch-name` |
+| Pull latest | `git pull origin main` |
+| Check status | `git status` |
+| View history | `git log --oneline` |
+| Switch branch | `git checkout branch-name` |
+| Delete branch | `git branch -d branch-name` |
+
+---
+
+## 🎊 You're Ready!
+
+Now you have a fully functional Git server for your E-Learning project! 
+
+**Next Steps**:
+1. Create repositories for each component (backend, frontend-student, frontend-admin)
+2. Invite team members
+3. Set up branch protection
+4. Start collaborating! 🚀