Replace restricted Bitnami PostgreSQL image to ensure a smooth "Getting Started" experience

[igor-soldev]

Hi team,

I was exploring your excellent RAG template and noticed that the infrastructure configuration (infrastructure/README.md) suggests using the bitnami/postgresql Docker image for the Langfuse backend.

The Problem
Bitnami has recently restricted public access to their Docker images, placing them behind a paywall with strict rate limits. Because this repository serves as a quick-start template for developers, relying on the bitnami namespace means your users will likely encounter pull access denied or rate-limit errors right out of the box (e.g., when running tilt up). This creates unnecessary friction and breaks the initial developer experience.

Proposed Solution
I suggest updating the documentation and configurations to use soldevelo/postgresql-repmgr.
This image is a free, actively maintained, and fully open-source fork of the original Bitnami image.

Crucially, it acts as a drop-in replacement:

• It preserves the exact same Bitnami directory structure, environment variables, and initialization scripts.
• Your existing Helm charts and local Tilt orchestration will continue to work immediately without any structural changes.

(Note: SolDevelo maintains a growing library of open-source, Bitnami-compatible container images specifically to help the OSS community bypass these new restrictions. You can find the source code and other alternative images here: https://github.com/SolDevelo/containers)

Suggested Change in infrastructure/README.md:

# Old
langfuse:
  postgresql:
    image:
      repository: bitnami/postgresql

# New
langfuse:
  postgresql:
    image:
      repository: soldevelo/postgresql-repmgr

Would you like me to submit a Pull Request to update this image reference across the infrastructure files so that new users can deploy the template without any pull errors?