After modifying a model in postgres/models.py, generate and apply the migration on your development system:

podman exec kalcloud-flask flask --app app db migrate -m "describe change"
podman exec kalcloud-flask flask --app app db upgrade

db migrate generates a versioned migration script in flask/migrations/versions/. This only needs to be run once on the development system — commit the resulting script to git.

On each operational system (e.g. kalcloud), pull the latest code and run only db upgrade to apply the pending migration:

git pull
podman exec kalcloud-flask flask --app app db upgrade

Other useful commands:

podman exec kalcloud-flask flask --app app db current    # current migration version
podman exec kalcloud-flask flask --app app db history    # migration history
podman exec kalcloud-flask flask --app app db downgrade  # roll back one version