Initial update work

This PR removes LDAP auth as we won't be using that and updates Rails and all gems to the most recent.

Most of the existing tests were not helpful (most failed from the start and appeared to be scaffolded). It's unclear how long we'll keep this around, so I haven't really written many tests. If we keep this around long, we'll want to write some tests (there's not really a lot of functionality so it won't be horrible).