Add README for Docker deployment

.dockerignore

@@ -4,14 +4,15 @@
 .idea
 .pylintrc
 .travis.yml
-package.json
 MANIFEST.in
 README.md
-requirements*.txt
 /debian
+!/debian/requirements.txt
 /doc
-/docker
+/docker/data
+/docker/pgdata
 /node_modules
 /tests
 /setup.*
 /*.sh
+!/pre-release.sh

docker/README.md

@@ -0,0 +1,19 @@
+# Docker Compose Deployment
+
+First download the files `docker-compose.yml` and `.env` from this directory.
+
+Decide on which domain name your repomaker instance will be running.
+Then generate a new secret key for your deployment.
+For example like so:
+
+    echo "REPOMAKER_SECRET_KEY=$(pwgen -cny 64 1)"
+
+Edit the downloaded file `.env` and put your domain name and your secret key there.
+
+Then start the docker containers:
+
+    docker-compose up
+
+If everything worked as it should,
+there should now be a repomaker instance running on your domain name.
+