Added the new save action

IndexController.php

<?php

...
    public function saveAction()
    {
        if ($data = $this->getRequest()->getPost()) {
            try {

                $model = $this->_initModel();

                if($model === false)
                {
                    throw new Exception("There was a problem saving the registry");
                }
                $customer   = Mage::getSingleton('customer/session')->getCustomer();

                // Update the model with the form data
                $model->updateRegistryData($customer, $data);
                $model->save();

                Mage::getSingleton('core/session')
                        ->addSuccess($this->__('The gift registry has been saved.'));

                if ($redirectBack = $this->getRequest()->getParam('back', false)) {
                    $this->_redirect('*/*/edit', array('id' => $model->getId(), 'store' => $model->getStoreId()));
                    return;
                }

            } catch (Mage_Core_Exception $e) {
                Mage::logException($e);
                Mage::getSingleton('core/session')->addError($e->getMessage());
                $this->_redirect('*/*/edit', array('id' => $model->getId()));
                return;
            } catch (Exception $e) {
                Mage::getSingleton('core/session')->addError($this->__('There was an error trying to save the gift registry.'));
                Mage::logException($e);
            }
        }
        $this->_redirect('*/*/');
    }