feat: implement user authentication with JWT and cookie management ISSUE #18

[AnirudhPhophalia]

Backend Authentication & User Management

This update adds a secure authentication system and user management to the IdeaVault backend, making it ready for production use.

Features Implemented

• User Model: Mongoose schema for users with name, email, password, and timestamps. Passwords are hashed using bcrypt.
• Authentication Routes:
  • POST /auth/register: Register a new user, validate input, hash password, and set JWT cookie.
  • POST /auth/login: Authenticate user, validate input, compare password, and set JWT cookie.
  • GET /auth/logout: Clear JWT cookie to log out user.
  • GET /auth/me: Fetch current logged-in user data (protected route).
• Security:
  • JWT tokens stored in HTTP-only cookies for secure session management.
  • Passwords hashed with bcrypt before saving to the database.
  • Auth middleware to protect private routes and verify JWT tokens.
  • Input validation using express-validator for all auth endpoints.
• MongoDB Integration: All user data is stored and managed using MongoDB via Mongoose.

Security Best Practices

• Passwords are never stored in plain text.
• JWT tokens are sent as HTTP-only cookies.
• All user input is validated before processing.

---