public async Task <UserParam> AddAsync(UserParam model)
        {
            _db.UserParams.Add(model);
            await _db.SaveChangesAsync();

            return(model);
        }
        public async Task UpdateAsync(UserParam model)
        {
            var entity = await _db.UserParams
                         .FirstOrDefaultAsync(rec => rec.Id == model.Id);

            if (entity != null)
            {
                entity.Name  = model.Name;
                entity.Value = model.Value;

                _db.UserParams.Update(entity);
                await _db.SaveChangesAsync();
            }
        }