Add tests

![http://media.tumblr.com/tumblr_m7or5ecmr41rter4a.gif](http://media.tumblr.com/tumblr_m7or5ecmr41rter4a.gif)

This project doesn't have any tests, so we should remedy that.
It'll be in the `.travis.yml` file as well.  Or should I put a comment explaining that you can install certain versions of Django on your machine if you want to run the tests locally, that sort of thing?  (In case we have more requirements later that Travis also needs.)