NilPortugues\Laravel5\JsonApi\Providers\Laravel51Provider::setJsonApiRelationships PHP Method

    protected function setJsonApiRelationships(ReflectionClass $mappingClass, $mapping)
    {
        $mappingProperty = $mappingClass->getProperty('relationshipSelfUrl');
        $mappingProperty->setAccessible(true);
        $relationshipSelfUrl = (array) $mappingProperty->getValue($mapping);
        if (!empty($relationshipSelfUrl)) {
            foreach ($relationshipSelfUrl as &$urlMember) {
                if (!empty($urlMember)) {
                    foreach ($urlMember as &$url) {
                        if (!empty($url['name'])) {
                            $url = $this->calculateRoute($url);
                        }
                    }
                }
            }
        }
        $mappingProperty->setValue($mapping, $relationshipSelfUrl);
    }