Ok I'm confused by 'environment variable' vs files. How does one set an environment variable without putting it in a file on the particular server. Or by 'file' in this article (and the 12 factor one) do they mean a file that in source control?
The article means 'file in source control' - the specific context is that the author is one of the co-founders of Heroku where there is a whole separate (really nice) system for handling 'config variables' as part of your app deployments separate from source control.
You can also run foreman if you're not on Heroku. Put your environment variables in a `.env` file. The environment variables get sourced only to the environment of that process and not to the __whole__ system