This repository uses https://docs.docker.com/develop/develop-images/multistage-build/ builds. If you're using Project Atomic/RHEL Docker, your best bet is to build OpenShift imagebuilder docker.
If you're going to iterate a lot on the host, it's recommended to stand up
a persistent "pet" development container, install rpm-ostree inside that,
as well as persistent OSTree repositories.
You'll also want to use the --cachedir argument to avoid repeatedly
downloading RPMs. More information in
the rpm-ostree docs.