How to specify "extra_hosts" in app store custom install?

[lisu9789]

I need to get the real host IP address instead of localhost from inside the container. I'm able to use

extra_hosts:
- host.docker.internal:host-gateway

I don't seem to be able to find way to specify this in the custom install form. Anyone has idea how to do it? I can do a CLI build but CasaOS would treat it as legacy. It would take a rebuild by CasaOS but the migraded docker-compose.yml doesn't have the "extra_hosts" entry, Therefore, the rebuilt container doesn't work any more. This means I can not get the "lagecy" app to merge to a real app store app. Does anyone have suggestion to solve this problem? It can only work if I build the container manually from CLI and leave it as "Legaccy" app in the CasaOS desktop. This means I can't launch it from CasaOS although it is a fully functional container.