* Enable having created file match the local user:group
If you run `docker compose up` with no other arguments, the `process_models` directory and everything in it will be created with `root:root` ownership. That's not great for the local editing use-case.
With this change, running `UGID="$(id -u):$(id -g)" docker compose up` will result in any created files matching the ownership of the invoking user. If the user doesn't set `UGID`, then the existing ownership (`root:root`) is the the default.
* Remove the need to explicitly mark git repositories safe
By setting `*` for `safe.directory` when the image is built, we remove
the need to run `git config` when starting the app in Docker. This
enables the container to run as any user, not just `root`.
* Use local variable naming convention