Thanks you anon, but unfortunately that didn't work.
I also read about installing gdm and then do
#update-rc gdm defaults
but I'm not sure about it, nor about:
"I think you should install and use nodm, “an automatic display manager which automatically starts an X session at system boot”. It is extremely lightweight and works like a charm.
Create the file /etc/sv/nodm/conf and add the configuration like this:
Additionally, your .xinitrc has to be executable in order to work with nodm (chmod 555)."