text: const mqtt = require('mqtt');
  
  const APP_NAME = process.env.HEROKU_APP_NAME || 'mqtt-private-broker';
  const client = mqtt.connect(`ws://${APP_NAME}.herokuapp.com`);
  
  client.on('connect', function() {
    client.subscribe('myTopic');
  });
  client.on('message', function(topic, message) {
    context = message.toString();
    console.log(context);
  });
  