# File lib/rbot/irc.rb, line 1352
    def add_user(user, opts={})
      silent = opts.fetch(:silent, false) 
      if has_user?(user)
        warn "Trying to add user #{user} to channel #{self} again" unless silent
      else
        @users << user.to_irc_user(server_and_casemap)
      end
    end