Put chess messages in threads

[mikeyaworski]

When a challenge is created, start a thread and post all future messages in that thread. Add a column to the DB which stores which thread the game should go in. If the thread cannot be found or posted to for whatever reason, fall back to the current implementation where it just posts message in the channel.

[mikeyaworski]

be1998a02361a2bd0e3c016f93c3998d97f5c990