Deploying with Kamal using a locally built Ruby image

Yesterday, a new security release was published for Ruby, but the official docker images took a long time to become available. The Ruby team has it’s own docker repository, and they published a new version quickly, but it is Ubuntu based, so if you are using a smaller image, that might not be suitable for you. In case of a security release, you should wait too long and luckily you can still take things in your own hands and just build a Ruby image. I deploy my apps with Kamal, so here is a guide about how to do that in the future should you need.