public IActionResult Create([FromBody] Models.SheetModel model)
        {
            var authorId = User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier).Value;

            model.Id       = 0;
            model.AuthorId = authorId;
            _context.Sheets.Add(model);
            _context.SaveChanges();
            return(new JsonResult(model.Id));
        }
        public IActionResult Update([FromBody] Models.SheetModel model)
        {
            var authorId = User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier).Value;
            var oldModel = _context.Sheets.Where(o => o.AuthorId == authorId).FirstOrDefault(o => o.Id == model.Id);

            if (oldModel != null)
            {
                model.AuthorId = authorId;
                _context.Entry(oldModel).CurrentValues.SetValues(model);
                _context.SaveChanges();
                return(Ok(""));
            }
            return(BadRequest($"Model '{model.Id}' on Author '{User.Identity.Name}' doesnt exist"));
        }