It is designed to be used with heroku-buildpack-multi to combine it with the appropriate real buildpack for your app.
This is based on http://github.com/jayzes/heroku-buildpack-ffmpeg, which was in turn based on https://github.com/shunjikonishi/heroku-buildpack-ffmpeg
.buildpacks file to the root of your repo that contains this buildpack URL and your real buildpack URL:
Then create an application using the multi buildpack:
$ heroku create --buildpack https://github.com/ddollar/heroku-buildpack-multi
or configure an existing application:
$ heroku config BUILDPACK_URL=https://github.com/ddollar/heroku-buildpack-multi
You can verify that everything is properly installed by running the following command:
$ heroku run "pngquant -h"
Copy the snippet above into CLI.