title: Implementation file upload multiple yii2 not work
body: <p>I'm trying to implementation file upload multiple in yii2 not work. When I choose 2 images for upload, appears description "You can upload at most 1 file". I don't know why, and how to solution ?</p>
  
  <p><a href="https://i.stack.imgur.com/HnDKz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HnDKz.png" alt="enter image description here"></a></p>
  
  <p>This code in view </p>
  
  <pre><code>&lt;?php
  use yii\widgets\ActiveForm;
  use yii\helpers\Html;
  ?&gt;
  &lt;h1&gt;Gallery&lt;/h1&gt;
  &lt;?php $form = ActiveForm::begin(['options' =&gt; ['enctype' =&gt; 'multipart/form-data'] ]) ?&gt;
      &lt;?= $form-&gt;field($model, 'image[]')-&gt;fileInput(['multiple' =&gt; true]) ?&gt;
      &lt;div class="form-group"&gt;
          &lt;?= Html::submitButton('Submit', ['class' =&gt; 'btn btn-primary']) ?&gt;
      &lt;/div&gt;
  &lt;?php
  ActiveForm::end();  
  ?&gt;          
  </code></pre>
  
  <p>This code in controller </p>
  
  <pre><code>public function actionGallery()
          {
              $model = new \app\models\Gallery();
              if (\Yii::$app-&gt;request-&gt;post()) {
                  $model-&gt;image = \yii\web\UploadedFile::getInstances($model, 'image');
                      if ($model-&gt;validate()) {
                          foreach ($model-&gt;image as $file) {
                              $saveTo = 'uploads/' . $file-&gt;baseName . '.' . $model-&gt;$file-&gt;extension;
                                  if ($file-&gt;saveAs($saveTo)) {
                                      $model2 = new \app\models\Gallery(['image' =&gt; $file-&gt;baseName . '.' . $file-&gt;extension,
                                          ]);
                                      $model2-&gt;save(false);
                                  }
                              }
                              Yii::$app-&gt;session-&gt;setFlash('success', 'Success uploaded !');
                          }
                      }
                      return $this-&gt;render('gallery', ['model' =&gt; $model]);
          }
  </code></pre>
  
  <p>This code in model</p>
  
  <pre><code>&lt;?php
  
  namespace app\models;
  
  use Yii;
  use yii\web\UploadedFile;
  
  /**
   * This is the model class for table "gallery".
   *
   * @property integer $id
   * @property string $image
   */
  class Gallery extends \yii\db\ActiveRecord
  {
      /**
       * @inheritdoc
       */
      public static function tableName()
      {
          return 'gallery';
      }
  
      /**
       * @inheritdoc
       */
      public function rules()
      {
          return [
              [['image'], 'file', 'extensions' =&gt; ['png', 'jpg', 'gif'], ]
          ];
      }
  
      /**
       * @inheritdoc
       */
      public function attributeLabels()
      {
          return [
              'id' =&gt; 'ID',
              'image' =&gt; 'Image',
          ];
      }
  
  
  }
  </code></pre>