It appears that you need a second Node.js server to implement your custom resolvers deployed via docker. This second server merges its schema with the automatically generated schema from PG.

This is a bit disappointing. I was expecting to just "point" parts of the automatic schema to some cloud functions hosted anywhere (Now v2, Lambda, etc) much like what AppSync does. This would bring all the benefits of going serverless and decoupling the schema from implementation. Some cloud functions could be written in Node, but others could be written in Go in a different provider.