Create user from ldap

[mmackiew]

I have CAS service to authenticate user which search user in LDAP.
It would be nice if:
If user does not exist's in redmine it will be create from LDAP database. I mean to use build in LDAP authenticate service to search user and create it if it is found in LDAP. Other case redmine ask new user to fill in registriation form.
In my case user always will found because of CAS authentication. For me it is nicley on the fly user create.