private static function AddUpgradeProducts($id, $upgradeproducts)
{
$i = 0;
// Delete all the products related before adding the new one
ProductsUpgrades::delItemsbyProductID($id);
$upgrade = new Doctrine_Collection('ProductsUpgrades');
if (!empty($upgradeproducts)) {
foreach ($upgradeproducts as $item) {
$upgrade[$i]->upgrade_product_id = $item;
$upgrade[$i]->product_id = $id;
$i++;
}
$upgrade->save();
}
}