The author of the article, Ricky Robinett, created an app using PHP, Guzzle, and the SeatGeek API to track World Series ticket prices and receive notifications when prices drop. The app uses Twilio to send text messages with a reminder to buy tickets when it detects a price drop. To build this application, the author used Composer to manage dependencies, initialized a Guzzle client, and made requests to the SeatGeek API to retrieve data about upcoming Royals games. The app stores previous values in a file and compares them to current values to detect a price drop, triggering an SMS notification when it happens. The script is set up to run every hour as a cronjob.