code: protected void redirectToReferrer() {
          String referrer = context.requestHeader("Referer");
          referrer = referrer == null? context.contextPath()/*injector.getInstance(DeploymentInfo.class).getContextPath()*/ : referrer;
          redirect(referrer);
      }
docs: Redirects to referrer if one exists. If a referrer does not exist, it will be redirected to
  the root of the application.
  
  @return {@link HttpSupport.HttpBuilder}, to accept additional information.