public void AddIdentityToGroup(SecurityGroupSecurityIdentity conn)
 {
     context.SecurityGroupSecurityIdentities.Add(conn);
 }
 public void RemoveIdentityFromGroup(SecurityGroupSecurityIdentity groupConenction)
 {
     context.Entry(groupConenction.Group).State    = EntityState.Detached;
     context.Entry(groupConenction.Identity).State = EntityState.Detached;
     context.Entry(groupConenction).State          = EntityState.Deleted;
 }