Update of the base layout inclusion

Rather than including the base template layout I extend it in order to
be able to supercharge the template model.
Signed-off-by: Matthieu Berjon <matthieu.berjon@inria.fr>

django/templates/user.html

-{% include "base.html" %}
+{% extends "base.html" %}
 {% block title %}Test users{% endblock %}
 
 {% block content %}