/**
   * This function puts a form on your page, using $Form.
   */
   public function SignupForm() {
      $formSignup = new Form($this, "SignupForm", new FieldSet(
            new EmailField("Email", "","E-Mail Address")),
            new FieldSet(new FormAction("SignupAction", "Sign up"))//,
            //new RequiredFields("Email")
         );
      //return $formSignup;
      return $this->customise($formSignup)->renderWith(array('FormSignup'));
   }

   /**
   * This function is called when the user submits the form.
   */
   public function SignupAction($data, $form) {

      // Create a new Member object and load the form data into it
      $member = new Member();
      $form->saveInto($member);

      // Write it to the database. This needs to happen before we add it to a group
      $member->write();

      // Add the member to group. (Check if it exists first)
      if($group = DataObject::get_one('Group', "ID = $this->defaultGroupID")) {

         $member->Groups()->add($group);
         // Redirect to a page thanking people for registering
         Director::redirect('signup-thank-you/');
         
      } else {
         // Redirect to a failure page
         Director::redirect('signup-failure/');
      }
   }