public void UpdateData(IUser newUser)
        {
            List <IUser> usersInFile = FetchData();

            int userIndex = usersInFile.FindIndex(x => x.ID == newUser.ID);

            usersInFile[userIndex] = newUser;

            string unparsedData = ParserStrategy.Unparse(usersInFile.ToArray());

            AccessStrategy.OverwriteAllData(unparsedData);
        }