docker-compose can not create user and password for mongodb

I am following this mongo's official docker page to configure mongodb to start with authorization enabled along with creating user, password and a database. However, when I spin up docker-compose my nodejs component, it isn't able to connect to mongodb because there are no users created in mongodb side.

docker-compose.yml

version: "3"
services:
  nodejs:
    container_name: nodejs # How the container will appear when listing containers from the CLI
    build:
      context: .
      dockerfile: Dockerfile-nodejs
    user: node # The user to run as in the container
    working_dir: "/app" # Where to container will assume it should run commands and where you will start out if you go inside the container
    networks:
      - app # Networking can get complex, but for all intents and purposes just know that containers on the same network can speak to each other
    ports:
      - "3000:3000" # <host-port>:<container-port> to listen to, so anything running on port 3000 of the container will map to port 3000 on our localhost
    volumes:
      - ./:/app # <host-directory>:<container-directory> this says map the current directory from your system to the /app directory in the docker container
    command: # The command docker will execute when starting the container, this command is not allowed to exit, if it does your container will stop
      - ./wait-for.sh
      - mongodb:27017
      - --
      - /bin/sh
      - -c
      - npm install && npm start
    env_file: .env
    environment: 
      - MONGO_USERNAME=$MONGO_USERNAME
      - MONGO_PASSWORD=$MONGO_PASSWORD
      - MONGO_HOSTNAME=mongodb
      - MONGO_PORT=$MONGO_PORT
      - MONGO_DB=$MONGO_DB
    depends_on:
      - mongodb

  mongodb:
    image: mongo:4.1.8-xenial
    container_name: mongodb
    restart: always
    env_file: .env
    environment:
      - MONGO_INITDB_ROOT_USERNAME=$MONGO_USERNAME
      - MONGO_INITDB_ROOT_PASSWORD=$MONGO_PASSWORD
      - MONGO_INITDB_DATABASE=$MONGO_DB
    networks: 
      - app

networks:
  app:
    driver: bridge

Dockerfile-nodejs

FROM node:10

RUN apt update && apt install -y netcat

.env

MONGO_USERNAME=simpleUser
MONGO_PASSWORD=123456
MONGO_PORT=27017
MONGO_DB=simpleDb

app.js

const express = require('express');
var server = express();
var bodyParser = require('body-parser');

var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;

// getting-started.js
var mongoose = require('mongoose');
mongoose.connect('mongodb://simpleUser:123456@mongodb:27017/simpleDb', {useNewUrlParser: true});

server.use(passport.initialize());
server.use(bodyParser.urlencoded({ extended: true }));


passport.serializeUser(function (user, done) {
  done(null, user);
});

passport.deserializeUser(function (id, done) {
  done(null, id);
});

passport.use(new LocalStrategy(
  function (username, password, done) {
    var user = { username: username };
    return done(null, user);
  }
));

server.get('/', function(req, res) {
  res.send('Hello World');
});

server.post('/login', passport.authenticate('local', { failureRedirect: 'failure' }), function (req, res) {
  res.send('access granted');
});

server.listen(3000, function() {
  console.log('Example app listening on port 3000');
});

> docker ps

CONTAINER ID        IMAGE                COMMAND                  CREATED             STATUS              PORTS                    NAMES
aad21da1ed48        biblio_nodejs        "docker-entrypoint.s…"   5 minutes ago       Up 5 minutes        0.0.0.0:3000->3000/tcp   nodejs
24c200f341ac        mongo:4.1.8-xenial   "docker-entrypoint.s…"   5 minutes ago       Up 5 minutes        27017/tcp                mongodb

> docker-compose logs -f mongodb

2019-06-13T13:37:11.104+0000 I NETWORK  [listener] connection accepted from 192.168.0.3:53942 #2 (1 connection now open)
2019-06-13T13:37:11.110+0000 I NETWORK  [conn2] received client metadata from 192.168.0.3:53942 conn2: { driver: { name: "nodejs", version: "3.2.7" }, os: { type: "Linux", name: "linux", architecture: "x64", version: "4.14.116-boot2docker" }, platform: "Node.js v10.16.0, LE, mongodb-core: 3.2.7" }
2019-06-13T13:37:11.111+0000 I SHARDING [conn2] Marking collection admin.system.users as collection version: <unsharded>
2019-06-13T13:37:11.112+0000 I ACCESS   [conn2] Supported SASL mechanisms requested for unknown user 'simpleUser@simpleDb'
2019-06-13T13:37:11.127+0000 I ACCESS   [conn2] SASL SCRAM-SHA-1 authentication failed for simpleUser on simpleDb from client 192.168.0.3:53942 ; UserNotFound: Could not find user "simpleUser" for db "simpleDb"
2019-06-13T13:37:11.133+0000 I NETWORK  [conn2] end connection 192.168.0.3:53942 (0 connections now open)