Registry (Part 1)

Can register
- Will tell you if username is taken
- Directs to register page
- Registration is possible.

Todo:
- Date object. Right now it's just a string. Age is a default now.
Should calculate age directly from Date of Birth.
- Actual validation of fields
- Mock hard database (instead of soft database)
- Note that WE CANNOT DELETE USERS FROM DATABASE (the way it's
associated)