Is there any way to make it so users can opt themselves into (and out of) a usergroup? On my forum I have off-topic discussion forums that are only accessible if a member wishes to get in. In a forum software that I formerly used, I had it setup so people could just join the usergroup. With XF, the only way I've figured out to do it so far is to have members ask me and I manually place them into the usergroup. There's got to be a better way?