I think next RC you gonna be able to do it. Or maybe next version 1.1
You can use a client like dgraph-js to load JSON.
Also you can try my project of CLI (still alpha version) GitHub - MichelDiz/Dgraph-Digger-CLI: A simple CLI for Dgraph.. Just install it by cloning the repo and build and “yarn link”. Then you can do
digger live --json ./pathToJSON/family.json