1935 user integration test

[dannyprikaz]

Fixes #1935

What changes did you make and why did you make them ?

• Added integration tests for all API endpoints from /backend/routers/users.router.js

[jng34]

@dannyprikaz
From my understanding, the integration test differs from the unit test because the integration test actually makes calls to the database to see that everything is "integrated" and works, as opposed to unit testing, where each piece of code is tested in isolation. Is that an accurate explanation?

[jng34]

All tests passed! Looks good.

[JackHaeg]

Hi @dannyprikaz!

Looks like this PR is ready to be merged since @jng34 has reviewed & approved. Please merge as you see fit.