public function SortCategories() {
      // Check permission
      $this->Permission('Garden.Settings.Manage');
      
      // Set delivery type to true/false
      $TransientKey = GetIncomingValue('TransientKey');
      if (Gdn::Request()->IsPostBack()) {
         $TreeArray = GetValue('TreeArray', $_POST);
         $Saves = $this->CategoryModel->SaveTree($TreeArray);
         $this->SetData('Result', TRUE);
         $this->SetData('Saves', $Saves);
      }
         
      // Renders true/false rather than template  
      $this->Render();
   }