I read that article a few weeks ago in order to get a basic personal site server running on Heroku. I used a standard cabal setup and updated a few things.

end result here, which I think should serve as a good starter point for developing with Scotty:

https://github.com/chrissrogers/chrissrogers.com

For Heroku builds I used the following excellent buildpack

https://github.com/begriffs/heroku-buildpack-ghc