Implementing user registration, login, and logout functionalities

[gorkem-bwl]

Schema design:

• [x] Define the schema for the user table, including fields such as username, email, password (hashed), etc.

Registration endpoint:

• [x] Create an endpoint to handle user registration
• [x] Validate incoming user data (e.g., username uniqueness, password strength)
• [x] Hash and store passwords securely in the database

Login endpoint:

• [x] Implement an endpoint for user login
• [x] Verify user credentials against the stored data.
• [x] Generate and return a JWT (JSON Web Token) upon successful authentication.

Logout Endpoint:

• [x] Implement an endpoint for user logout.
• [x] Invalidate or expire the JWT token.

Session management:

• [x] Handle user sessions securely (e.g., token expiration, token refreshing)