public IActionResult AddTicket([FromBody] Ticket ticket)
        {
            if (!ModelState.IsValid)
            {
                return(BadRequest() as IActionResult);
            }
            var entity = service.AddTicket(ticket);

            return(entity == null?StatusCode(409) as IActionResult : Created($"{Request.Scheme}://{Request.Host}{Request.Path}{entity.Id}", entity));
        }