Auth: Restrict AdminIndexView to only admins.
Users.Views: Constrict user models to admin only.
Auth: Restrict AdminIndexView to only admins.
Users.Views: Constrict user models to admin only.
Merge hotfix-restrict-admin-to-only-admins (#59) into master

Constrict admin to only admin.

Only admins, as opposed to staff, can now access the admin panel.