app/controllers/triumph/achievements_controller.rb
def destroy
      @achievement = Achievement.find(params[:id])
      @achievement.destroy

      respond_to do |format|
        format.html { redirect_to(triumph_achievements_url) }
        format.xml  { head :ok }
      end
    end
def destroy
      @achievement = Achievement.find(params[:id])
      @achievement.destroy

      respond_to do |format|
        format.html { redirect_to(triumph_achievements_url) }
        format.xml  { head :ok }
      end
    end
DELETE /achievements/1
 DELETE /achievements/1.xml