Don't merge: Friends

There are a couple todos, so I wanted to get some ideas before this gets merged:

1. I should probably cache the friends query from facebook. Redis is my answer unless you think something better has come along lately.

2. If you hit the explore page directly before logging in, I don't know your friends and can't show their reviews. We can either block the explore page until the user logs in (which I'm not in favor of) or just not show the friend's reviews until the user is logged in. I'll need to learn more about angular before I can figure out the second way.