As an admin, I want: an overview over registered users

Userstory: As an admin I want an overview over registered users. I want to see the username, status and a button where I can manage the user.

![dr_web3](https://cloud.githubusercontent.com/assets/7096588/2626196/ffc8c9b8-bdc1-11e3-91d5-c9b1e1c1332b.png)