fix: resolve Docker container SQLite database path issue

- Updated database path from relative 'backend/chat_data.db' to absolute '/app/backend/chat_data.db'
- Modified docker-compose.yml to mount entire backend directory for proper database persistence
- Updated Dockerfile.backend to ensure backend directory exists in container
- Fixes GitHub issue #849: sqlite3.OperationalError unable to open database file

Co-Authored-By: PromptEngineer <jnfarooq@outlook.com>

Dockerfile.backend

@@ -16,8 +16,8 @@ RUN pip install --no-cache-dir -r requirements.txt
 COPY backend/ ./backend/
 COPY rag_system/ ./rag_system/
 
-# Create necessary directories
-RUN mkdir -p shared_uploads logs
+# Create necessary directories and initialize database
+RUN mkdir -p shared_uploads logs backend
 
 # Expose port
 EXPOSE 8000

backend/database.py

@@ -5,7 +5,7 @@ from datetime import datetime
 from typing import List, Dict, Optional, Tuple
 
 class ChatDatabase:
-    def __init__(self, db_path: str = "backend/chat_data.db"):
+    def __init__(self, db_path: str = "/app/backend/chat_data.db"):
         self.db_path = db_path
         self.init_database()
     

docker-compose.yml

@@ -57,7 +57,7 @@ services:
       - NODE_ENV=production
       - RAG_API_URL=http://rag-api:8001
     volumes:
-      - ./backend/chat_data.db:/app/backend/chat_data.db
+      - ./backend:/app/backend
       - ./shared_uploads:/app/shared_uploads
     depends_on:
       rag-api: