20241116 - code refactoring, database implementation and unitary testing

[luisfelix-93]

What I did

1. Database implementation:

• I've implemented a database layer to be able to:
  a) Manage users;
  b) Store user messages

2. Code refactoring

• Here I've refactored the code to use an easy-to-understand architecture, and to help with scalability in the future

3. Unitary Testing

• I also implemented a sequence of unit tests to help with the development of related improvements, and to be able to act on bugs more precisely in the future.

packages used:

• mongoose
• jest
• mongodb-memory-server
• redis-mock