public ActionResult <Folder> GetFolder(int id)
        {
            Folder folder = _folderRepository.GetBy(id);

            if (folder == null)
            {
                return(NotFound());
            }
            return(folder);
        }
        public bool FolderExists(int id)
        {
            var folder = _folderRepository.GetBy(id);

            return(folder != null);
        }