Users can view dive sites

https://trello.com/c/SrGeblPt/3-users-can-view-site-details

![image](https://cloud.githubusercontent.com/assets/8681076/5076279/d9ea19ca-6e67-11e4-9b0e-f7a7461c4673.png)

If the `save` fails, you won't have the ivar when you render the `:new` view...