gistfile1.rb

  def create
    if saved = @act.add_participant(@current_person)
      flash[:notice] = _('You are now participating in this action!')
    else
      flash[:notice] = @act.errors.full_messages.first
    end

    respond_to do |format|
      format.html { redirect_to(@act) }
      format.xml  { head :ok }
      format.json { render :json => {:answer => (saved ? 2:1), :message => flash[:notice] }}
    end
  end