TODO

- automatching
    - support picking players that are closest to requestor's skill level
        - use Elo rating for skill level

- support > 2 players
    - match keys {pN, nameN, statsN}
    - how to configure "start after N have joined"?
    - how to configure max players for rules of play?
        - part of automatch params?
    - after match: only update elo rating if 2 players

- direct matchmaking
    - names are non-unique though; what to do if > 1 user is found?
        - would be good to support a way to support "friends"
    - queue/channel for each user so challenges can be sent
    - what about blocking people?
    - can of worms
    - after match:
        - do not update ratings
        - do not transfer coins

- store "important" match events?
    - keep the most recent 10K or something
    - allow client to ask server for match events after some id thereafter
    - only real thing a client can do when opponent goes offline is pause the
      game which is not a great ux

- offer different products for each platform
    - store products as hash of platform => JSON([{id,coins}])

- online tournaments
    - group 8 random players in a sit-and-go
    - location based using Redis' GEO commands for grouping
backup completed messages offsite (e.g. aws)