old_contents: var Express = require('express')
  
  function FacebookMessengerClient() {}
  
  FacebookMessengerClient.prototype.start = function(bot) {
  
    var app = Express()
  
    app.get('/', function (req, res) {
      res.send('BotKit is running.')
    })
  
    app.get('/webhook', function(req, res) {
      if (req.query['hub.mode'] === 'subscribe' &&
          req.query['hub.verify_token'] === VALIDATION_TOKEN) {
        console.log("Validating webhook");
        res.status(200).send(req.query['hub.challenge']);
      } else {
        console.error("Failed validation. Make sure the validation tokens match.");
        res.sendStatus(403);
      }
    });
  
    app.listen(80) // FIXME: Set port in env
  };
  
  FacebookMessengerClient.prototype.speak = function(message) {
    console.log(message);
  }
  
  module.exports = FacebookMessengerClient;
  
new_contents: var Express = require('express')
  
  function FacebookMessengerClient() {}
  
  FacebookMessengerClient.prototype.start = function(bot) {
  
    var app = Express()
  
    app.get('/', function (req, res) {
      res.send('BotKit is running.')
    })
  
    app.get('/webhook', function(req, res) {
      if (req.query['hub.mode'] === 'subscribe' &&
          req.query['hub.verify_token'] === VALIDATION_TOKEN) {
        console.log("Validating webhook");
        res.status(200).send(req.query['hub.challenge']);
      } else {
        console.error("Failed validation. Make sure the validation tokens match.");
        res.sendStatus(403);
      }
    });
  
    app.listen(3000)
  };
  
  FacebookMessengerClient.prototype.speak = function(message) {
    console.log(message);
  }
  
  module.exports = FacebookMessengerClient;
  
subject: Fix url.