public async Task <IHttpActionResult> AddAdmin([FromBody] Admin admin)
        {
            ValidationError[] validationErrors = await adminService.AddAdminAsync(admin, User.Identity.Name);

            if (validationErrors.Length == 0)
            {
                ApplicationMemoryCache.Instance.Remove("GetAllAdmins()");
                return(Ok());
            }

            return(BadRequest(validationErrors[0].Message));
        }