Start writing web server

If you run the server, it creates one test user in the database, so the only things you can really do currently are `GET /hello` and `GET /user/1`.
I thought about this and decided against `Location`s being related to `Waypoint`s for a few reasons. We probably want to have an "official" lat/lon for a location, and we want to mark people's journeys as starting or ending there even if they weren't exactly at that lat/lon. It seems cleaner to me if every waypoint belongs to a journey; if we adhere to that, then it doesn't make sense to have a location tied (indirectly) to a particular journey, and we might not even get any waypoints at precisely the lat/lon where we want the location to be. Also, it doesn't make sense for a location to have a time and an accuracy attached.

So the idea is, somebody records a journey and a bunch of waypoints get saved. Then, based on the first and last waypoint (and sometimes some user interaction), we decide which locations to mark the journey as starting and ending at.