Replace docker usage section in README

Author: manisandro

README.md

@@ -165,24 +165,8 @@ This expression is a serialized JSON array of the format:
 Docker usage
 ------------
 
-To run this docker image you will need a PostGIS database. For testing purposes you can use the demo DB.
+See sample [docker-compose.yml](https://github.com/qwc-services/qwc-docker/blob/master/docker-compose-example.yml) of [qwc-docker](https://github.com/qwc-services/qwc-docker).
 
-The following steps explain how to download the demo DB docker image and how to run the `qwc-data-service` with `docker-compose`.
-
-**Step 1: Clone qwc-docker**
-
-    git clone https://github.com/qwc-services/qwc-docker
-    cd qwc-docker
-
-**Step 2: Create docker-compose.yml file**
-
-    cp docker-compose-example.yml docker-compose.yml
-
-**Step 3: Start docker containers**
-
-    docker-compose up qwc-data-service
-
-For more information please visit: https://github.com/qwc-services/qwc-docker
 
 Development
 -----------