Fix for Issue #3

This seems to get it working for me...please let me know if it doesn't work for you, or if you have any questions. There seemed to be a factory service missing, so I added it. Also seems like the payload referred to below was originally the entity, but has since been abstracted a level further.

This project is saving us a tremendous amount of work at my workplace - this sort Apigility functionality is hugely underrated for legacy systems. Thanks!