BRANCH 2 Create a 'User' object

#### Feature/Bug Description
- Added a 'User' object

#### How Feature/Bug Fix was implemented
- Object code is stored in a MongoDB collection

#### Video of Change
- No video was made for this Pull Request

#### Tests Added
- test delete_users
- test create_user
- test create_user (duplicate)
- test create_user (username null)
- test create_user (username is one char)
- test create_user (username is two chars)
- test create_user (username starts with a non alpha char)
- test create_user (username too long)

#### Areas of Regression
- None

#### Automation
- [ ] Pull Request Requires Automation

#### Code Reviewers
- [x] None