Update main.py

[abhigyaabs2]

1. Title: Refactored database table creation into FastAPI startup event
Description:
The database tables were created using Base.metadata.create_all() at the top-level script. This can lead to unexpected behaviors in production or during test runs.
Fixes:
Moved the table creation logic into a FastAPI @app.on_event("startup") function to ensure tables are only created when the app start

2. Title: Added CORS middleware support for frontend integration
Description:
To allow cross-origin requests from the frontend (e.g., React/Vue app), CORS headers has be added. Without CORS middleware, requests from different origins (e.g., frontend on localhost:3000) may be blocked.

Fixes:
Used FastAPI’s CORSMiddleware to enable cross-origin requests.

3. Title: Enhanced Swagger UI with route tags

Description:
The routes in Swagger (docs) were ungrouped. Adding tags while including routers will help organize them logically and improve developer usability.

Fixes:
Used:
app.include_router(favorites.router, tags=["Favorites"])