resolvers2.js

import { delegateToSchema } from 'graphql-tools';

const resolvers = {
  Blog: {
    user(parent, args, context, info) {
       return delegateToSchema({
        schema: userSchema,
        operation: 'query',
        fieldName: 'userById',
        arges: { id: parent.userId },
        context,
        info,
      });
    },
  },
};