title: Laravel administrator before_save() is not firing
body: <p>I am getting userid from sentry and when creating or updating records, I need to update user_id to the posts too. I am using before_save() callback on the config.<code>Sentry::getUser()-&gt;id</code> is working correctly(i checked the function on routes and it is correctly providing user_id). While creating a post through administrator,  user_id is not being updated and hence the error.
      
  
  <pre><code>/**
   * app/config/administrator/posts.php
   */
  
  return array(
  
      'title' =&gt; 'Posts',
  
      'single' =&gt; 'post',
  
      'model' =&gt; 'Post',
  
      /**
       * The display columns
       */
      'columns' =&gt; array(
          'user' =&gt; array(
              'title' =&gt; 'User',
              'relationship' =&gt; 'user',
              'select' =&gt; "(:table).email",
          ),      
          'category' =&gt; array(
              'title' =&gt; 'Category',
              'relationship' =&gt; 'category',
              'select' =&gt; "(:table).name",
          ),  
          'pricing' =&gt; array(
              'title' =&gt; 'Pricing',
              'relationship' =&gt; 'pricing',
              'select' =&gt; "(:table).name",
          ),
          'name' =&gt; array(
              'title' =&gt; 'Name',
              'select' =&gt; "name",
          ),
          'title' =&gt; array(
              'title' =&gt; 'Title',
              'select' =&gt; "title",
          ),
          'description' =&gt; array(
              'title' =&gt; 'Description',
              'select' =&gt; "description",
          ),
          'order' =&gt; array(
              'title' =&gt; 'Order',
              'select' =&gt; "order_value",
          ),
          'active_date' =&gt; array(
              'title' =&gt; 'Start',
              'select' =&gt; "active_date",
          ),
          'expiry_date' =&gt; array(
              'title' =&gt; 'End',
              'select' =&gt; "expiry_date",
          ),
          'status' =&gt; array(
              'title' =&gt; 'Status',
              'select' =&gt; "status",
          )
      ),
  
      /**
       * The filter set
       */
      // 'filters' =&gt; array(
      //  'name' =&gt; array(
      //      'title' =&gt; 'Name',
      //  ),
      //  'description' =&gt; array(
      //      'title' =&gt; 'Description',
      //      'type' =&gt; "text",
      //  )
      // ),
  
  
      'before_save' =&gt; function(&amp;$data)
      {
          $data['user_id'] = Sentry::getUser()-&gt;id;
          // return $data;
      },
  
      /**
       * The editable fields
       */
      'edit_fields' =&gt; array( 
          'category' =&gt; array(
              'title' =&gt; 'Category',
              'type' =&gt; 'relationship',
              'name_field' =&gt; "name",
          ),  
          'pricing' =&gt; array(
              'title' =&gt; 'Pricing',
              'type' =&gt; 'relationship',
              'name_field' =&gt; "name",
          ),
          'name' =&gt; array(
              'title' =&gt; 'Name',
              'type' =&gt; "text",
          ),
          'title' =&gt; array(
              'title' =&gt; 'Title',
              'type' =&gt; "text",
          ),
          'description' =&gt; array(
              'title' =&gt; 'Description',
              'type' =&gt; "textarea",
          ),
          'active_date' =&gt; array(
              'title' =&gt; 'Start',
              'type' =&gt; "date",
          ),
          'expiry_date' =&gt; array(
              'title' =&gt; 'End',
              'type' =&gt; "date",
          ),
          'status' =&gt; array(
              'title' =&gt; 'Status',
              'type' =&gt; "bool",
          )
      ),
  
  
  );
  </code></pre>