I have been maintaining a jruby image for the "official" docker images program (https://github.com/docker-library/official-images) for several years now.
These are being built from https://github.com/cpuguy83/docker-jruby.

Unfortunately I have not really been part of the Ruby community in quite some time and am rather disconnected, and even more so with the Java community.

Recent changes with bundler 2.0 highlight this.
There's also some things that I really don't have the bandwidth or know-how to investigate: jruby/docker-jruby#42 jruby/docker-jruby#37

Wanted to reach out and see if you'd be up to taking over maintenance for this, perhaps as part of your release process.

Let me know, thanks!