Подписки Graphql не отображают новые дополнения к базе данных

Question

Я следую этому уроку. Мой полный код здесь.

Многие люди говорят, что подписка не работает. Я не знаю причину этого. Я думаю проблема в том { where: { mutation_in: ['CREATED'] } } в Subscription.js

Subscription.js
const newLink = {
  subscribe: (parent, args, ctx, info) => {
    return ctx.db.subscription.link(
      { where: { mutation_in: ['CREATED'] } },
      info,
    )
  },
}

const newVote = {
  subscribe: (parent, args, ctx, info) => {
    return ctx.db.subscription.vote(
      { where: { mutation_in: ['CREATED'] } },
      info,
    )
  },
}

module.exports = {
  newLink,
  newVote,
}

index.js
const { GraphQLServer } = require('graphql-yoga')
const { Prisma } = require('prisma-binding')
const Query = require('./resolvers/Query')
const Mutation = require('./resolvers/Mutation')
const Subscription = require('./resolvers/Subscription')

const resolvers = {
  Query,
  Mutation,
  Subscription
}

const server = new GraphQLServer({
  typeDefs: './src/schema.graphql',
  resolvers,
  context: req => ({
    ...req,
    db: new Prisma({
      typeDefs: 'src/generated/prisma.graphql',
      endpoint: "https://us1.prisma.sh/public-surfape-281/hackernews-graphql-js/dev",
      secret: 'mysecret123',
    }),
  }),
})

server.start(() => console.log('Server is running on http://localhost:4000'))

schema.graphql
# import Link, Vote, LinkSubscriptionPayload, VoteSubscriptionPayload from './generated/prisma.graphql'

type Query {
  feed(filter: String, skip: Int, first: Int): [Link!]!
}

type Mutation {
  post(url: String!, description: String!): Link!
  signup(email: String!, password: String!, name: String!): AuthPayload
  login(email:String!, password:String!):AuthPayload
}
type AuthPayload {
  token: String
  user: User
}
type Subscription{
  newLink:LinkSubscriptionPayload
  newVote:VoteSubscriptionPayload
}