gistfile1.txt

<?php
/**
 * Description
 *
 * @package silverstripe
 * @subpackage mysite
 */
class MealCategory extends DataObject
{
  /**
   * Database fields
   * @var array
   */
  private static $db = array(
    'Category' => 'Varchar',
    'Description' => 'Text',
  );

  /**
   * Belongs_many_many relationship
   * @var array
   */
  private static $belongs_many_many = array(
    'MenuItems' => 'CateringMenuItem',
  );

  private static $summary_fields = array(
    'Category' => 'Category Name',
    'DefaultPrice' => 'Default Price',
  );

  /**
   * Changes the default title DBField for all internal Silverstripe functionality
   * NOTE: If you have a DataObject with no "Name" or "Title" DBField this MUST be set
   */
  function getTitle()
  {
    return $this->Category;
  }

  public function getCMSfields() {
    $fields = parent::getCMSFields();
    // Get the grid that was automatically created for the Many_many relationship
    $relationGridfield = $fields->fieldByName("MenuItems");
    // Remove the tab that was automatically created for the Gridfield
    $fields->removeByName("Root.MenuItems");
    // Move the Already existing Gridfield to a different sub-tab
    $fields->addFieldToTab('Root.AssignedMenuItems', $relationGridfield);

    return $fields;
  }
}