Use multiple buildpacks on your app
$ heroku buildpacks:set https://github.com/ddollar/heroku-buildpack-multi.git $ cat .buildpacks https://github.com/heroku/heroku-buildpack-nodejs.git#0198c71daa8 https://github.com/heroku/heroku-buildpack-ruby.git#v86
MIT