Sylius Product Bundle configuration
问题 I'm trying to integrate Sylius Product Bundle into my existing Symfony project. It already has doctrine configured. This is the error I am getting: [Symfony\Component\Config\Definition\Exception\InvalidConfigurationException] The child node "driver" at path "sylius_attribute" must be configured. Any idea what's causing this? I followed the instruction right off the bat without doing any other installations of sylius. http://docs.sylius.org/en/latest/bundles/SyliusProductBundle/installation