Killpack/auth *WIP* *WIP* *WIP*

WIP.

It's gonna work like this:
- You type in your username and password, which hits the `authorizations` endpoint. On successful authentication, it returns your auth token.
- Ember stores this auth token somewhere and uses it to make requests from thereon out.
I think `link-to` only works for real paths, not actions. And since `logout` is an action, we can't use it.

But this comment made me realize that the `logout` path in the router doesn't actually go anywhere.