What is the aim of docker/Dockerfile.xeus-cling_with_compilers ?

I am not sure this docker is still useful for the training ? We just mention its existence in the README.md:

The lengthy `registry.gitlab.inria.fr/formations/cpp/gettingstartedwithmoderncpp/xeus-cling-and-compilers` is the name of the Docker **image**, if this image is not present locally in your environment Docker will try to fetch it from a *registry* on the Inria Gitlab. 

and in the docker/README.md

- [Dockerfile.xeus-cling_with_compilers], which creates an image with a Conda environment to run properly Xeus-cling and installs as well local compilers so that they may be invoked from the notebooks (for the 6-InRealEnvironment part).

In this image, there are all the xeus-cling requirements, plus cmake and g++. I don't even know how to run the container to do some c++/cmake.

In exercises and InRealEnvironment, we advise to use the fedora image instead.

(This is more a question than an issue)