Update student_interface.html.erb

Creates errors like this:
![screen shot 2014-09-29 at 12 39 52 pm](https://cloud.githubusercontent.com/assets/5453617/4445173/44267bf4-47f7-11e4-8b5b-9f50300b04d9.png)
when it should actually look like this: 
![screen shot 2014-09-29 at 12 40 45 pm](https://cloud.githubusercontent.com/assets/5453617/4445195/6bdc2c84-47f7-11e4-8eab-1f6c3d80ca9f.png)