Implement and test socket.io, router, and user authentication

[martin-markovic]

Description

This pull request introduces several features and enhancements to the project:

1. Development Dependencies: Added socket.io, socket.io-client, nodemon, supertest, mongoose, mocha, chai, and chai-http as development dependencies via npm install --save-dev.

2. Test Script Addition: Included a test script in package.json for streamlined testing.

3. Socket.io Integration: Integrated Socket.io with the HTTP server (server.js).

4. Socket.io Testing: Implemented server.test.js to validate Socket.io functionality, ensuring it handles client connections/disconnections and starts the server using expect, server, PORT, and io.

5. User Authentication: Implemented user authentication controller functions registerUser and loginUser in userController.js and integrated them into userRoutes.js.

6. User Authentication Testing: Implemented userAuth.test.js to validate user authentication and routing functionality, ensuring it handles post requests and authenticates users using expect, request, express, and userRouter.

Context

These changes were necessary to enhance the project's real time capabilities with Socket.io, streamline the testing process, and improve user authentication mechanisms.

Impact

• The new dependencies will make the development environment more robust.
• Socket.io integration will allow real-time communication features.
• The added tests ensure that new features work correctly and existing functionality remains unaffected.

Instructions

• Run npm install to install the new development dependencies.
• User npm test to run the newly added tests and ensure everything is working correctly.