/**
  * @return \yii\db\ActiveQuery
  */
 public function getCurrency()
 {
     return $this->hasOne(Currency::className(), ['id' => 'currency_id']);
 }
 /**
  * @return \yii\db\ActiveQuery
  */
 public function getCurrencies()
 {
     return $this->hasMany(Currency::className(), ['user_id' => 'id']);
 }