/**
 * use \mdm\upload\FileModel
 *
 * ganti News::$thumnail_url dengan News::$image_id, tipenya integer.
 *
 */
public function actionCreate()
{
    $model = new News();
    $model->scenario = 'create';
    if($model->load(Yii::$app->request->post())){
        $file = UploadedFile::getInstance($model,'image');
        $model->image = $file;
        //...
        if($model->validate() && ($fmodel=FileModel::saveAs($file, Yii::$app->params['uploadPath']))!==false){
            $model->image_id = $fmodel->id;
            $model->save();
            Yii::$app->session->setFlash('success', 'Upload Success');
            return $this->redirect(['view','id'=>$model->id]);
        }else{
            // ...
        }
    }
}