I need to roll my own Gitea package for Alpine fairly often, because the published builds don't support MySQL, which is my choice of a database backend. (A container image making use of it is available here.) Sometimes I build other packages as well, even if only bumping versions - I'm a self-confessed early adopter of latest releases and I'm not always willing to wait for the maintainers.
I decided to eventually automate this process using Ansible and published my solution prototype here. It's somewhat peculiar in the sense that it uses containers implemented by libpod as I no longer run Docker.
I've published another, similar repository here which I use to build actual container images.
Perhaps they shall prove useful for contemporary peers as well as posterity - as always: comments and pull requests are welcome.