Update repositories view. Database layout changed once more.

* We now store the avatar URL instead of the avatar id. Theres no warnings when doing an HTTPS request when we're on HTTP, only the other way arround.
* Dropped the account token for the hooks. The application will register directly against GitHub, all the user will have to do is enable it's repository.
* The repository now has 2 self explanatory attributes instead of just `active`, `push_active` and `pull_active`.
* We now have an improved view of the repositories we belong to.
Add 404 template.