title: add Export Button Group to yajra datatable laravel package
body: <p>I am using <a href="https://github.com/yajra/laravel-datatables" rel="nofollow noreferrer">yajra laravel datatables</a> package version <strong>6.0</strong> and I want to add export button group But I do not know how can I implement that.</p>
  
  <p>Suppose I have a <code>SubscriberController</code> class like this :</p>
  
  <pre><code>public function newsletterDatatable (Request $request) {
      $subscribers =  Subscriber::select(['sub_id', 'email', 'confirmed', 'created_at']);
  
      $datatable = app('datatables')-&gt;of($subscribers)
          -&gt;orderBy('created_at', 'desc')
          -&gt;addColumn('checkbox', '&lt;input type="checkbox" name="item_id[]" value="{{$sub_id}}"&gt;');
  
          return $datatable-&gt;make(true);
      }
  </code></pre>
  
  <p>And in JS codes I have :</p>
  
  <pre><code>$('#allSubscribersTable').DataTable({
      processing: true,
      serverSide: true,
      "bSort": false,
      "responsive": true,
      dom: 'Bfrtip',
      buttons: [
          'copy', 'csv', 'excel', 'pdf', 'print'
      ],
      ajax: {
          url: '{!! route('admin.newsletterDatatable') !!}'
      },
      columns: [
          {data: 'checkbox', "width": "20px"}
      ]
  });
  </code></pre>
  
  <p>As you can see I used <code>buttons</code> option on DataTable initialization but when table is shown there are not any export buttons.</p>
  
  <p>On the <a href="https://yajrabox.com/docs/laravel-datatables/6.0/buttons-export" rel="nofollow noreferrer">buttons-export</a> page on Docs is said that I should add below Code But I do not know where and how to use in my controller :</p>
  
  <pre><code>namespace App\DataTables;
  
  use App\User;
  use Yajra\Datatables\Services\DataTable;
  
  class UsersDataTable extends DataTable {
      //...some default stubs deleted for simplicity.
  
      public function html() {
          return $this-&gt;builder()
                      -&gt;columns($this-&gt;getColumns())
                      -&gt;parameters([
                          'buttons' =&gt; ['export'],
                      ]);
      }
  ...
  </code></pre>
  
  <p>If anyone know please help me.</p>