code: public function SignupUser($moniker, $mailer_id = null)
      {
          $endpoint = '/user/signup';
          $postdata = array("moniker" => $moniker, "mailer_id" => $mailer_id);
          return $this->executePostRequest($endpoint, $postdata);
      }
docs: Sign up a user for a chance to participate in the beta.
  
  @param string $moniker Something to uniquely identify the user, usually an email address.
  @return type