public IActionResult Post(int participantId, [FromBody] Notice notice)
        {
            var participant = _dbContext.Participants.FirstOrDefault(p => p.Id == participantId);

            if (participant == null)
            {
                return(NotFound());
            }
            participant.Notices.Add(notice);
            _dbContext.SaveChanges();
            return(NoContent());
        }
        public IActionResult Post([FromBody] Participant participant)
        {
            //participants.
            //participants.Add(participant);
            if (participant == null)
            {
                return(BadRequest());
            }
            _dbContext.Participants.Add(participant);
            _dbContext.SaveChanges();

            return(new NoContentResult());
        }