title: How to add a class to <td> tags in a GridView
body: <p>I need to add classes to td of a GridView.
  I've found <a href="http://www.yiiframework.com/doc-2.0/yii-helpers-basehtml.html#renderTagAttributes()-detail">renderTagAttributes()</a>, but I can't find examples how to use it.
  Could you explain me this function or offer me other option?</p>
  
  <p>My gridview:</p>
  
  <pre class="lang-php prettyprint-override"><code> &lt;?= GridView::widget([
      'dataProvider' =&gt; $dataProvider,
      'filterModel' =&gt; $searchModel,
      'columns' =&gt; [
          ['class' =&gt; 'yii\grid\SerialColumn'],
          'id',
          'name',
          'price',
          'quantity',
          'created_at',
          [
              'class' =&gt; 'yii\grid\ActionColumn',
              'template' =&gt; '{update} {delete}',
          ]
      ],
  ]); ?&gt;
  </code></pre>
  
  <p>Thanks in advance</p>