Remove user vars from 404 page.
Add and view challenges.
Added challenge admin tab; start and end times to db.
Add or remove admins.
Retreive pull requests.
Join challenge and get pull req for registered users.
Some user restrictions on challenges.
Add pull req merge date, title and url.
Add challenge repos and contact email.
Get created, merged pull req count.
Add challenge status, logo and repo list.
Added styling for challenges page.
Add about tab to challenge page.
Pad date on challenge admin tab.
Get individual repo created/merged counts.
Style challenge stats.
Style commits tab.
Style about tab. Add challenge about atribute.
Style users tab.
Add functionality to joined button.