Improve open command logic

Fix dublicate checks in tests

Final build

Final touches

Merge branch 'main' of https://github.com/PKolev26/Library

Improve users read from file and local memory logic

Update README.md

Update README.md

Add comments in the code

Add test cases for the program

Hide password with * on login

Rebuild booksFind to be case-insensitive

Add more help commands

Add saveas command

Add book remove command