Could this be a 2 step docker build

I recently started using 2 step docker builds for node based stuff. This way I have node, npm, and all the dependencies installed in my build container, but my final container only contains the code + node itself.

Anyway, I'm not really sure about the details of how elixir works. But I suspect that some of the stuff required for the build process isn't then required for the running container. My first question then, is that true?

If it is, would you be open to a PR which switches the docker file to use a 2 step approach? I can't promise I can make it work, or that I will submit a PR at all, but before I tried I wanted to check.