I'm trying to use a user other than SA to create new users on a SQL Server 2014 base, I've tried the db_accessadmin and db_securityadmin roles yet, but they do not permissions to change other roles.
For example, when I create a user, I want to allow the db_datareader and db_datawriter roles for this user, but I do not have permissions.
Anyway, does anyone know how to do this?