How do I know whether my Rails app is thread-safe or not?This is The Den, a publication crafted by the friendly cubs at Bear Metal. Photo by Joseph Francis, used under a Creative Commons license. In January Heroku started promoting Puma as the preferred web server for Rails apps deployed on its hugely successful platform. Puma – as a threaded app server – can better use the scarce resources available for an app running on Heroku. This is obviously good
