Filter the username creation
Lately I've actually had a troll named Timmy Turner who would come in and spam the n-word Non-Stop and whenever I would ban him he would create another account just to come in and spam again. But I turned followers only mode on, but he thinks he found a loophole by talking to me through the usernames. And of course he's being a butthole through username as well. How about make it so that you can't create a username that has any rude words like idiot, or threatening words like Riot, or any other swear word.
