code: public ButtonTemplateBuilder addUrlButton(String title, String url,
  			WebViewHeightRatioType ratioType) {
  		Button button = ButtonFactory.createUrlButton(title, url, ratioType);
  		this.payload.addButton(button);
  		return this;
  	}
docs: Adds a button which redirects to an URL when clicked to the current
  template. There can be at most 3 buttons.
  
  @param title
  the title of the url button
  @param url
  the actual link of the this url button
  @param ratioType
  the size of the web view url.
  @return
  this builder