users endpoint and index of all users

[loftwah]

People keep seeming to end up on /users (dunno how I'm doing that). Instead of just fixing that I thought I could add an attribute where users can opt-in to a public index of users and the users can all be indexed there with links to their profile. I'd be interested to know how people were getting to /users.

[loftwah]

We should fix the route too.

[loftwah]

#112

[loftwah]

This is good. Next issue is to add user opt-in and also the leaderboard.