In order for the [`Listener` in `rvic-daccs`](https://github.com/pacificclimate/rvic-daccs/issues/17) that will be used for the [progress bar in the `osprey-flask-app`](https://github.com/pacificclimate/osprey-flask-app/issues/7) to be accessible by the app, the port number used by this listener should be exposed in this container.