Do setup when connected to server.

        - Join the primary channel.
        - Join the control channel.

def do_welcome(self):
        """Do setup when connected to server.

        - Join the primary channel.
        - Join the control channel.

        """
        self.rate_limited_send('join', self.config['core']['channel'])
        self.rate_limited_send('join', self.config['core']['ctrlchan'], self.config['auth']['ctrlkey'])
        # We use this to pick up info on admins who aren't currently in a channel.
        self.workers.defer(5, False, self.get_admins)
        extrachans = self.config['core']['extrachans']
        if extrachans:
            for chan in [x.strip() for x in extrachans.split(',')]:
                self.rate_limited_send('join', chan)