/// <summary> Add specified user in a role </summary>
public override void AddUserToRole(string userName, string roleName)
{
// TUser user = UserManager.FindByName(userName);
TUser user = UserStore.FindUserByName(userName);
if (user == null)
{
throw new ArgumentNullException(string.Format("Unknown user {0}", userName));
}
// UserManager.AddToRole(user.UserId, roleName);
UserStore.AddUserToRole(user, roleName);
}