Can't connect to an IPv6 DB from the app container

[mattgibson]

I've just tried setting up Rails on a cloud server via Kamal and providing connection details to a free supabase DB, which is IPv6 only. I get a Network Unreachable error from ActiveRecord on deploy, and the same happens when I use psql from inside the container. If I SSH into the instance and use psql outside the container, it connects correctly.

Not sure if #1280 or something similar will fix it

[HLFH]

@mattgibson Yes, my PR #1280 fixes it. Please use it.