[kevinsimper]

I like they way they highlight that combining Ruby and nodejs makes for a complicated Dockerfile, while their example after only includes Ruby and not nodejs. And do they propose a buildpack called ruby-nodejs, because in many cases you don't need nodejs in your Ruby app. OMG now buildpack's are a leaky abstraction!

[codefinger]

The Ruby buildpack shown in the example installs Node.js for you. A developer doesn’t even need to be aware that it’s required to precompile assets.

[molszanski]

If only we lived in a universe where there was an easy to find and ready to use dockerpack ruby-node. Oh wait.

[jacques_chester]

The CNB design allows buildpacks to opt in or out as a group. So the same nodejs buildpack can work in multiple usecases. With ruby, java, whatever's necessary.