[Request] Game reminders

[ghost]

!remindme <game> <number of turns> <message>

e.g. !remindme testgame 12 NAP with ermor expires: bot PMs you "NAP with ermor expires" after 12 turns have passed in testgame
!remindme 2 build fort in 98: bot PMs you "build fort in 98" after 2 turns have passed for the game named after the channel the reminder was created in

maybe also !reminder for channels

e.g. !reminder 6 peoples arena: bot messages the current channel "peoples arena" after 6 turns have passed for the game the reminder was created for