/**
  * Signs user up.
  *
  * @return Users|null the saved model or null if saving fails
  */
 public function register()
 {
     if ($this->validate()) {
         /** @var Users $user */
         $user = Yii::createObject(Users::className());
         $user->setScenario('register');
         $user->setAttributes($this->attributes);
         return $user->register();
     }
     return false;
 }
 /**
  * @return \yii\db\ActiveQuery
  */
 public function getUser()
 {
     return $this->hasOne(Users::className(), ['id' => 'user_id']);
 }