code: @Override
      public Renderable<?> render(Controller controller) {
          return render(controller, Collections.<String, Object>emptyMap());
      }
docs: Renders the template. Unlike {@link #render(org.wisdom.api.Controller, java.util.Map)},
  this method does not inject any user variables.
  
  @param controller the controller having requested the rendering.
  @return the rendered object.