I added metrics to a simple Rails app using ruby-metrics and Telegraf, which are used in conjunction with InfluxDB for data storage and visualization through Chronograf. The author started by adding the necessary middleware to their Rails app and then configured Telegraf to collect metrics from the app's '/stats' endpoint. They then set up an output plugin to write the collected data to InfluxDB, a time-series database that can handle large amounts of data and provide insights into trends over time. The author was able to visualize their metrics in Chronograf, creating a dashboard with a graph showing the total number of requests per minute for the previous five minutes. While their solution felt good during the discovery phase, it has some limitations, such as only running locally and not addressing production concerns. The author is now looking to further improve their app's performance by monitoring its database and container performance, and exploring ways to measure failures and successes.