code: public static function sendWelcomeMessage(User $user)
  		{
  			return Mailer::sendMail($user->email, 'Welcome to ' . Yii::$app->name, 'welcome', ['user' => $user]);
  		}
docs: Sends welcome mail to the user upon registration
  
  @param \abhimanyu\user\models\User $user
  
  @return bool