Welcome to the API!

How to utilise this API:

• POST /signup : Register a new user. The payload should be a JSON object containing 'username' and 'password' keys.
• POST /login : Authenticate an existing user. The payload should be a JSON object with 'username' and 'password' keys. This endpoint returns a JWT token when successful.
• GET /logout : Invalidate a user's JWT token. This endpoint does not require a payload.