docs, README: Update Docker instructions

Mention the official image and be a bit more clear about
config requirements.

Dockerfile

@@ -86,7 +86,7 @@ CMD ["/isso/bin/gunicorn", "-b", "0.0.0.0:8080", "-w", "4", "--preload", "isso.r
 # $ docker build -t isso .
 #
 # Run:
-# $ mkdir config
-# $ cp contrib/isso-dev.conf config/isso.cfg
-# $ mkdir db/
-# $ docker run -d --rm --name isso -p 8080:8080 -v $PWD/config:/config -v $PWD/db:/db isso:latest
+# $ mkdir -p config/ db/
+# $ cp contrib/isso.sample.cfg config/isso.cfg
+# Set 'dbpath' to '/db/comments.db' and adjust 'host'
+# $ docker run -d --rm --name isso -p 127.0.0.1:8080:8080 -v $PWD/config:/config -v $PWD/db:/db isso:latest

README.md

@@ -42,6 +42,12 @@ If you're stuck, follow the [Install guide](https://isso-comments.de/docs/refere
 see [Troubleshooting](https://isso-comments.de/docs/guides/troubleshooting/) and browse
 the [the full documentation](https://isso-comments.de/docs/).
 
+## Docker
+
+A Docker image with the latest stable release is provided at
+`ghcr.io/isso-comments/isso:latest`. See
+[Using Docker](https://isso-comments.de/docs/reference/installation/#using-docker).
+
 ## Contributing
 - Pull requests are very much welcome! These might be
   [good first issues](https://github.com/posativ/isso/labels/good-first-issue)

docs/docs/reference/installation.rst

@@ -137,16 +137,39 @@ Prebuilt Packages
 
 * Arch Linux: https://aur.archlinux.org/packages/isso/
 
-Build a Docker image
---------------------
+.. _using-docker:
 
-You can get a Docker image by running ``docker build . -t isso``.
-Assuming you have your configuration in ``/opt/isso``, you can use the
-following command to spawn the Docker container:
+Using Docker
+------------
+
+Assuming you have your configuration in ``/opt/isso``, with
+``dbpath=/db/comments.db`` and ``host`` set properly in ``isso.cfg``, you have
+two options for running a Docker container:
+
+a) Official Docker image
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block:: console
+
+    $ docker pull ghcr.io/isso-comments/isso:latest
+    $ docker run -d --rm --name isso -p 127.0.0.1:8080:8080 \
+        -v /opt/isso:/config -v /opt/isso:/db \
+        ghcr.io/isso-comments/isso:latest
+
+b) Build a Docker image yourself
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+You can build a Docker image by running ``make docker``, which will be tagged
+as ``isso:latest``.
 
 .. code-block:: console
 
-    $ docker run -d --rm --name isso -p 127.0.0.1:8080:8080 -v /opt/isso:/config -v /opt/isso:/db isso
+    $ mkdir -p config/ db/
+    $ cp contrib/isso.sample.cfg config/isso.cfg
+    # Set 'dbpath' to '/db/comments.db' and adjust 'host'
+    $ docker run -d --rm --name isso -p 127.0.0.1:8080:8080 \
+        -v $PWD/config:/config -v $PWD/db:/db \
+        isso:latest
 
 Then, you can use a reverse proxy to expose port 8080.