Add Helm chart

[ljubon]

Action items with merging this PR:

• Create docker environment
  • Create environment variable RUBY_VERSION with value 3.3.4
  • Create environment variable RAILS_ROOT with value /app
• Check https://github.com/G-Research/astral/settings/actions
  • The Workflow permissions should have enabled Read and Write permissions in order to be able to push docker image to Github Container registry with GITHUB_TOKEN. If this is not acceptable or we don't have option to change this we should instead use PAT

Below you can find CLI command to test the chart and run application within k8s cluster:

# Install kind - tool to run k8s cluster inside single container required for testing helm chart and used during development
# https://kind.sigs.k8s.io/docs/user/quick-start/#installation

# Helm manifests to-be-deployed
helm template astral . -f values.yaml > debug.yaml 

kind create cluster --name astral

# Make sure that before this, image is built within CI and push 
# (development image was ghcr.io/g-research/astral:latest) 
kind load docker-image ghcr.io/g-research/astral:latest -n astral

helm install astral -f ./helm/values.yaml ./helm

kubectl logs deployment/astral

# Cleanup
helm uninstall astral
kind delete cluster --name astral

[suprjinx]

Looks great, thanks!