Cannot connect to database using internal url

[joshfester]

To Reproduce

1. Create a postgres database
2. Create a Ruby on Rails app in the same project
3. Set the DATABASE_URL env variable to the internal postgres url

Current vs. Expected behavior

When trying to deploy a Rails app using nixpacks, I get this error:

PG::ConnectionBad: could not translate host name "northcentralai-postgres-031ff5" to address: Name or service not known (PG::ConnectionBad)

Is there some extra step to make the postgres host name available to the rails app?

Provide environment information

OS: Ubuntu 24.04
Host: Hetzner
Dokploy: 0.10.0
Postgres Image: postgres:16
Ruby: 3.3.5

Which area(s) are affected? (Select all that apply)

Application, Databases

Additional context

No response

[joshfester]

I tried switching the builder to use a Dockerfile and I tried Heroku Buildpacks. Both ran into the same issue connecting to the database

[Siumauricio]

Duplicate of #507