implemented crud operations for users

[matia-lee]

Notion ticket link

Users CRUD https://www.notion.so/uwblueprintexecs/Users-CRUD-1fe10f3fb1dc80d38489ce80acfb25cd?pvs=4

Implementation description

• implemented incomplete endpoints related to users

Steps to test

What should reviewers focus on?

Checklist

• My PR name is descriptive and in imperative tense
• My commit messages are descriptive and in imperative tense. My commits are atomic and trivial commits are squashed or fixup'd into non-trivial commits
• I have run the appropriate linter(s)
• I have requested a review from the PL, as well as other devs who have background knowledge on this PR or who will be building on top of this PR