sub commands: help, add, remove, list, add-channel, remove-channel, list-channel
run sub command with / ban [subcommand]
show help message of sub commands by / ban help [subcommand]
show current message with / ban help
make this bot exec random command, Usage:
/ rand chance1,chance2,chance3 command1 | command2 | command3
for example: / rand 1,2.5,3 say 1 | say 2 | say 3