The export workflow reusing the `/consume` volume is complex and error-
prone, and not at all necessary if the `docker-compose.yml` file has a
volume for `/export` from the beginning.
This commit adds a `Dockerfile` to the root of the project, accompanied
by a `docker-compose.yml.example` for simplified deployment. The
`Dockerfile` is agnostic to whether it will be the webserver, the
consumer, or if it is run for a one-off command (i.e. creation of a
superuser, migration of the database, document export, ...).
The containers entrypoint is the `scripts/docker-entrypoint.sh` script.
This script verifies that the required permissions are set, remaps the
default users and/or groups id if required and installs additional
languages if the user wishes to.
After initialization, it analyzes the command the user supplied:
- If the command starts with a slash, it is expected that the user
wants to execute a binary file and the command will be executed
without further intervention. (Using `exec` to effectively replace
the started shell-script and not have any reaping-issues.)
- If the command does not start with a slash, the command will be
passed directly to the `manage.py` script without further
modification. (Again using `exec`.)
The default command is set to `--help`.
If the user wants to execute a command that is not meant for `manage.py`
but doesn't start with a slash, the Docker `--entrypoint` parameter can
be used to circumvent the mechanics of `docker-entrypoint.sh`.
Further information can be found in `docs/setup.rst` and in
`docs/migrating.rst`.
For additional convenience, a `Dockerfile` has been added to the `docs/`
directory which allows for easy building and serving of the
documentation. This is documented in `docs/requirements.rst`.
