Using TransactionScope with Entity Framework code first and universal providers
using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required))
{
    MembershipCreateStatus createStatus;
    MembershipUser user = Membership.CreateUser(model.UserName, model.Password, model.UserName, null, null, true, null, out createStatus);

    //add objects to the DbContext db

    db.SaveChanges();
    scope.Complete();