Isn't a bug however, when someone is demoted, it says congratulations. I think it should be changed to something along the lines of "Bad luck" or something like that.

The /promote and /demote commands aren't actually real commands. They're "fake" commands that hook into the /setrank command. This setrank command sets the users rank, and plays a standard message. I'll have a look to see if the destination rank is lower than their current, and change the message accordingly. :3