Some modifications were in order so that gitlab-mirrors
works with the latest pyapi-gitlab.

This fixes issue #2 reported by @lmakarov.

Fixes issue #2

Update installation.md to include adding group to gitlab

Note about "Mirrors" group creation step in gitlab

If run in a cron job and gitlab is off-line update_mirror.sh
would turn the SVN repository into a bare repository.  This
then breaks the SVN mirror until bare is set back to false.

Major bugfix a working directory bug where
crontab execution fails.

This way users can utilize gitlab-mirrors as well as Administrators.

For installing prerequisites the python-gitlab doc was missing
the install command.

There's no need to move the project to a group if the user is
creating projects in their own namespace.

Rewrote some of the docs as well to be more eloquent.

with group namespace resolution.
upstream merge request for python-gitlab.

up to this point.

preflight check did not properly test it.

Will temporarily reference my forked project.