I got Redline running on heroku with almost no fuss. https://stout.herokuapp.com/
The only change to redline itself was to make it read the server port from the env instead of hard coded to 8080: https://github.com/will/redline-smalltalk-heroku/commit/ce4112cf48cb9e992457aed7008cf3fce5e822b3 It should probably thread the port from an argument to the stout script, but I don't really know java.
The only other steps were adding a procfile and setting the redline_home env var, and that was it. Pretty easy.