[services] don't hardcode 'users' group for register_user
Let the caller choose which group the user should be in. Related to #3020639
Caveat: this is a possible security hole if untrusted values are allowed.
.. -*- coding: utf-8 -*-
.. _Part1:
--------------------------
Introduction to *CubicWeb*
--------------------------
This first part of the book offers different reading path to
discover the *CubicWeb* framework, provides a tutorial to get a quick
overview of its features and lists its key concepts.
.. toctree::
:maxdepth: 2
:numbered:
history
concepts.rst