API documentation for WIP#162

This PR isn't ready to be merged in yet, it's just there to keep everybody in the loop with what I'm doing.

Basically, I'd like to get the API up and documented so we can start testing it with Apiary and also so it's easier to implement. At the moment a lot of the data in the app is locked away without an API and that doesn't really go with the Assembly philosophy. This documentation is to help that happen.