public ActionResult Approve(SaveApprovalViewModel viewModel)
        {
            var request  = viewModel.MapTo <ApproveSignatureRequest>();
            var response = _signatureService.ApproveSignature(request);
            var data     = new
            {
                id             = response.Id,
                userId         = response.UserId,
                type           = response.Type.ToString(),
                signatureImage = response.SignatureImage,
                approve        = response.Approve,
                reject         = response.Reject,
                note           = response.Note
            };

            return(Json(data, JsonRequestBehavior.AllowGet));
        }