[gdm-list] change default behaviour of gdm from gnome to gnome-fallback

[magina antimage <magina the antimage 001 gmail com>]

Hi,
         When i try to run gdm in gnome mode it crashes so i am running it in gnome-fallback mode
but whenever i create a new user by default it sets gdm to run in gnome and not in gnome-fallback so i have to set it into gnome-fallback manually
every time i create a new user...
can anyone tell me is it possible to get gnome-fallback mode by default for every user i create using useradd

thanks,
Regards
Lokesh