private void MoveTopic(IDatabaseContext ctx, DiscussionTopic topic, int targetFolderId)
        {
            PermissionContext.VerifyPermission(PermissionToken.DeleteComments);

            var folder = ctx.Load <DiscussionFolder>(targetFolderId);

            ctx.AuditLogger.AuditLog(string.Format("Moving {0} to {1}", topic, folder));

            topic.MoveToFolder(folder);
        }