Support for embedded struct type in resolver

[gxb5443]

I would like my resolver to expand on an existing struct type, like from another package, when using UseFieldResolvers. To do that, I compose the objects by embedded the base struct inside the resolver struct. However, this doesn't compile because it looks like graphql-go only traverses the first level of fields to find the one that satisfies the schema. This would be helpful so I don't have to implement tedious resolver methods for every field.

package resolvers

import "github.com/gxb5443/project1/users"

type AdminResolver struct {
  users.Admin
}

[jseibert]

Strongly agreed. This would allow composing GraphQL types from DB types while keeping them separate, without requiring tons of boilerplate.

[eloyekunle]

In progress: #338

[dnutels]

This is a fairly crucial topic. Ambiguity should be resolved in the same manner all other issues with schema -> type are resolved, by panicing on mismatch, just like a missing resolver does.

Separating the types, which should really be auto-generated and external to the client code, from the resolvers is an extremely valuable thing.