User Login System

[sirexeclp]

As an annotation provider, I want to manage multiple users (Annotators) to work on my data.

Acceptance Criteria

• [x] multiple users
• [x] login page
• [x] login required
• [x] user info of the current user is saved with annotation
• [x] script to add new user
• [x] multiple users can annotate the same image without data loss