gistfile1.php

public function linkCustomerAction($id)
    {
        $customer = $this->getDoctrine()->getRepository('PugMRestDemoBundle:Customer')->find($id);
        $links = $this->getRequest()->attributes->get('links');
        foreach($links as $invoice){
            $customer->addInvoice($invoice);
        }

        $this->getDoctrine()->getManager()->flush();
    }