Read existing 'schema.json' to serve querys/mutations

If we could read an existing `schema.json` file, for creating the types, queries and mutations allowed by the server, it would be great for frontend development...

Another improvement would be generating "Loren Ipsun"-style data for each type.

This is specially useful for other backend languages/frameworks (Flask, Django, Rails, etc) that generates `schema.json` file.