<?php
class ProductPage extends Page {
	private static $has_many = array(
		'RelatedProducts' => 'ProductPage'
	);

	public function getCMSFields() {
		$fields = parent::getCMSFields();
		$products = Product::get()->exclude(array('ID' => $this->ID));
		$gridfieldConfig = GridFieldConfig::create();
		$gridfieldConfig->addComponent(new GridFieldManyRelationHandler($this, 'RelatedProducts'));
		$gridField = new GridField('products', 'Related Products', $products, $gridfieldConfig);
		$fields->addFieldToTab('Root.RelatedProducts', $gridField);

		return $fields;
	}
}