Add docker usage section to README

Author: manisandro

README.md

@@ -197,6 +197,12 @@ Examples:
 
     curl -g 'http://localhost:5011/geom/ne_10m_admin_0_countries/?filter=[["ogc_fid","=",90]]'
 
+Docker usage
+------------
+
+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).
+
+
 Testing
 -------