public function verifyEmail($id, $verificationKey)
 {
     /**
      * @var $email Email
      */
     $email = Email::whereId($id)->whereVerificationKey($verificationKey)->first();
     if (is_null($email)) {
         return redirect('/')->withErrors(['Invalid email verification URL.']);
     }
     $email->verified = true;
     $email->save();
     return redirect('/');
 }