Simplify instructions for exporting with docker

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.

docker-compose.yml.example

@@ -23,6 +23,12 @@ services:
             # You have to adapt the local path you want the consumption
             # directory to mount to by modifying the part before the ':'.
             - /path/to/arbitrary/place:/consume
+            # Likewise, you can add a local path to mount a directory for
+            # exporting. This is not strictly needed for paperless to
+            # function, only if you're exporting your files: uncomment
+            # it and fill in a local path if you know you're going to 
+            # want to export your documents.
+            # - /path/to/another/arbitrary/place:/export
         env_file: docker-compose.env
         command: ["document_consumer"]
 

docs/migrating.rst

@@ -74,40 +74,20 @@ as JSON is almost as easy:
 
     $ docker-compose run --rm webserver dumpdata documents.Tag > /path/to/arbitrary/place/tags.json
 
-Exporting the documents though is a little more involved, since docker-compose
-doesn't support mounting additional volumes with the ``run`` command. You have
-three general options:
+To export the documents you can either use ``docker run`` directly, specifying all
+the commandline options by hand, or (more simply) mount a second volume for export.
 
-1. Use the consumption directory if you happen to already have it mounted to a
-   host directory.
+To mount a volume for exports, follow the instructions in the
+``docker-compose.yml.example`` file for the ``/export`` volume (making the changes
+in your own ``docker-compose.yml`` file, of course). Once you have the
+volume mounted, the command to run an export is:
 
 .. code-block:: console
 
-       $ # Stop the consumer so that it doesn't consume the exported documents
-       $ docker-compose stop consumer
-       $ # Export into the consumption directory
-       $ docker-compose run --rm consumer document_exporter /consume
-
-2. Add another volume to ``docker-compose.yml`` for exports and use
-   ``docker-compose run``:
-
-   .. code-block:: diff
-
-      diff --git a/docker-compose.yml b/docker-compose.yml
-      --- a/docker-compose.yml
-      +++ b/docker-compose.yml
-      @@ -17,9 +18,8 @@ services:
-               volumes:
-                   - paperless-data:/usr/src/paperless/data
-                   - paperless-media:/usr/src/paperless/media
-                   - /consume
-      +            - /path/to/arbitrary/place:/export
-
-   .. code-block:: shell-session
-
    $ docker-compose run --rm consumer document_exporter /export
 
-3. Use ``docker run`` directly, supplying the necessary commandline options:
+If you prefer to use ``docker run`` directly, supplying the necessary commandline
+options:
 
 .. code-block:: shell-session