Custom Fields CodeIgniter Tank Auth Registration

I'm using Codeigniter with TankAuth. I have done practically zero editing to the default tank auth files.

I want to开发者_运维百科 be able to add some fields to auth.php that gets sent to tank_auth->create_user so that a user account is created with some additional fields.

I have tried doing it in the standard add the vars to be passed but it's not working. I'm sure its probably quite simple to do this but I'm at my wits end with lack of sleep trying to sort it.

Any help would be great,thanks.