Hi,
Thanks for your plugin!
I'd like to draw your attention to this question and answer on Stack Overflow:
https://stackoverflow.com/questions/26999365/play-framework-2-3-6-java-javascripts-and-stylesheets-not-found-when-deployed
I'm not the author but I had the exact same problem that could be solved by replacing sbt-rjs with sbt-uglify, as mentioned in the question's answer.
Is there some kind of incompatibility between sbt-rjs and Heroku?
I'm using sbt-rjs 1.0.7.
Let me know if I can provide any more detail on the issue.
Thanks in advance!