After creating a Pakyow app on my local computer and pushing it up to Heroku using the steps detailed here, the app fails to serve pages with the error message "No web processes running" displayed in the server logs, and the default "Application Error" message being displayed on the website user's side.
Upon initiating the "git push heroku master" command, two of the messages that appear while it's deploying are: "No Procfile detected, using the default web server (webrick)" and at a later point "Procfile declares types -> (none)"
Although I am not certain this is a Procfile issue, it does appear that the various messages point to the lack of a Procfile being the cause.