Create admin namespace

https://trello.com/c/iqzQ3SyP/16-create-a-namespace-for-admins

![image](https://cloud.githubusercontent.com/assets/8646429/5171012/4ad033e8-73e2-11e4-9678-a9acd5991a51.png)

Oh, it inherits from `AdminController`, so it's only for admins. I think of admins as being system-wide privileged people (e.g. you), so why only let admins edit their own charity? Why not let them edit any charity? Am I missing something?