Ship docker images with readme

docker/Dockerfile

@@ -11,6 +11,8 @@ RUN venv/bin/pip install -e .[test,examples,docs,examples_unix]
 WORKDIR /
 RUN mkdir scripts
 ADD startup.sh scripts/
+ADD readme.md /
+
 # Due to the nature of the Docker container it might often be built from Windows.
 # It is typical to have the files with \r\n line-ending, we want to remove it for the unix image.
 RUN sed -i 's/\r//g' scripts/startup.sh

docker/readme.md

@@ -10,6 +10,9 @@ This document contains information about:
  3. [Versions](#versions) help you identify which image to use.
  4. [Developer](#for-developers) information about the Docker image.
 
+*note:* each docker image is shipped with a readme, which you can read with:
+`docker run --entrypoint=/bin/cat openml/openml-python:TAG readme.md`
+
 ## Usage
 
 There are three main ways to use the image: running a pre-installed Python environment,