Is there an API call to set the default login environment?

hi @vincent,
i think my purpose was not clear.
I want to create a rancher cluster, create one admin user, some environments, and stacks, all stored in a git repository, and populated via ansible.
I can ship via ansible a cluster (server and agents).
But i cannot create in the cluster, a first admin user with a github id (cf Enable github access via API).
If you can provide an example of an API call to create in the rancher cluster an admin user by referencing a github id, or some oauth stuff from github), it will be very useful.

best regards,
Charles.