Heroku + Node "Error: Cannot find module '../config.js' Require stack: - /app/util/check-auth.js, - /app/graphql/resolvers/posts.js, - /app/index.js

Question

My app is running fine locally but after deploying with Heroku I get Application Error.

This are my Heroku logs

This is my project structure:

{
  "name": "merng",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "serve": "node index.js",
    "start": "node index.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "apollo-server": "^2.5.0",   
     "bcryptjs": "^2.4.3",
     "graphql": "^15.3.0",
      "jsonwebtoken": "^8.5.1",
    "mongoose": "^5.10.10"
  },
  "devDependencies": {
    "nodemon": "^2.0.6"  
  }
}