Make use of GitHub's "Deployments Dashboard" (in Beta)

https://help.github.com/en/github/administering-a-repository/viewing-deployment-activity-for-your-repository

Heroku appears to already support some of this stuff, which is probably why the repository for Prout (which is currently deployed to Heroku) has all of this extra gubbins:

https://github.com/guardian/prout/deployments

