It's a very simple PHP app used for Jenkins versions rating on https://jenkins.io/changelog, and which stores its data in a PostgreSQL backend.
https://github.com/jenkins-infra/helm-charts/tree/main/charts/rating
Edit files, then make run to launch a dockerized version of the app with a temporary test database.
Run make run-test to make sure the program is functional.
Run docker-compose down to wipe out the test database content.