text: const initRoutes = require('./init-routes');
  const connectDB = require('./init-db');
  const checkInSubscriber = require('../pubSub/check-in-subscriber');
  const checkOutSubscriber = require('../pubSub/check-out-subscriber');
  const { createQueue } = require('../utils/notificationQue');
  const notificationWorker = require('../utils/notificationWorker');
  
  /**
   * @function
   * Initializes app components
   *
   * @param {object} app - Express app.
   */
  module.exports = (app) => {
    initRoutes(app);
    connectDB();
    checkInSubscriber();
    checkOutSubscriber();
    createQueue();
    notificationWorker.start();
  };
  