Make attendance form sharable

This will be used at our church so that students can submit class attendance from iPads without signing in.

![screen shot 2014-10-11 at 7 27 11 pm](https://cloud.githubusercontent.com/assets/669/4604784/883ad9c4-51b7-11e4-8577-2afa43facbd3.png)

![screen shot 2014-10-11 at 7 29 42 pm](https://cloud.githubusercontent.com/assets/669/4604787/a713068c-51b7-11e4-8afa-e8e342018a37.png)