Currently everything is stashed in a static folder on the host OS which is fine for the most part but can be limiting as it comes to Dockers full capabilities. Its helpful to be able to have everything in docker containers so you can duplicate your deployment environment to a staging machine if you want to test changes to your environment without effecting service.
What I propose.
An extra /var/discourse/sample/storage.yml where it simply just adds a storage container which can be easily pushed to a private Docker repository.
It can add complexity to have everything in separate containers but thats generally what Docker recommends so that you can replace the moving bits independent of other moving bits.
- Portability, you can clone a docker container and push them to a personal repository on the docker registry or even a self hosted registry if you so desire.
- Compatibility with clustering operating systems such as CoreOS