Add "best practices" in README

README.rst

@@ -194,3 +194,24 @@ To run cubicweb looping tasks, you will also have to start the ``scheduler``::
 
    # run in background
    docker run -d --restart=always --name myapp-scheduler myapp cubicweb-ctl scheduler instance
+
+
+Best practices
+--------------
+
+In case of source tree builds, add a ``.dockerignore`` to your project to avoid
+copying useless files inside the docker image. For example::
+
+   .*
+   *.egg-info
+   **/__pycache__
+   Dockerfile
+   Jenkinsfile
+   Makefile
+   tox.ini
+   test
+   debian
+
+
+Always pull the base image before running the build. Base images are rebuild in
+case of debian security update or new pypi releases.