Explains what the image does, which variables are required (five),
usually set, or already defaulted to production, and lists the secrets.
Then deployment three ways: plain docker run with SQLite on a volume,
Docker Compose with PostgreSQL, and Kubernetes with Helm, with
configuration injected as environment and migrations as a separate
pre-install/pre-upgrade Job. Ends with checks after deploying and a
troubleshooting table. Linked from the README.
