resolvers.js

resolvers: {
  RootQuery: {
    posts: () => posts,
    post: async (_, { id }) => 
      await Post.query()
  },
  RootMutations: {
    createPost: async (_, { input }) => 
      await Post.query.insert(input)
  },
  RootSubscriptions: {
    postAdded: {
    subscribe: () => 
      pubsub.asyncIterator('postAdded')
  },
  Post: {
    author: async post => 
      await Usuario.query().where("id", "=", post.author_id)
  }
}