text: var express = require('express');
  var bodyParser = require('body-parser');
  var request = require('request');
  var app = express();
  
  app.use(bodyParser.urlencoded({extended: false}));
  app.use(bodyParser.json());
  app.listen((process.env.PORT || 3000));
  
  // Server frontpage
  app.get('/', function (req, res) {
      res.send('This is TestBot Server');
  });
  
  // Facebook Webhook
  app.get('/webhook', function (req, res) {
      if (req.query['hub.verify_token'] === 'testbot_verify_token') {
          res.send(req.query['hub.challenge']);
      } else {
          res.send('Invalid verify token');
      }
  });