public function saveAction()
 {
     $invoicesTable = new Invoices();
     $form = $this->getNewInvoiceForm();
     if ($form->isValid($_POST)) {
         $values = $form->getValues();
         $data = array('customer_id' => $values['customer'], 'invoice_date' => $values['invoice_date'], 'due_date' => $values['due_date'], 'notes' => $values['notes']);
         $id = $invoicesTable->insert($data);
         $this->_redirect('/invoices/view/id/' . $id);
     } else {
         echo $form;
     }
 }