SQLiteness

A few thoughts on this cached users db:

* I do not restart the bot frequently, which means that this cached data will become out of date after a checkin, or a bet, etc, unless we also update the cache at the same time we update the db.... which seems expensive and redundant. Maybe caching users this way is actually not going to be an advantage. 
* Isn't the notation for a global variable an @ sign? I don't think I've seen $variable before in ruby... have you tested this code, does it work?
* I think for the sake of clarity we should store the user attributes as sub-hashes rather than a sub-array, so that in the code we can call users[nick][points] instead of users[nick][1], which is sort of like having poor code documentation.