public void SaveToFile(journal j, string filename, bool overwrite = false)
 {
     if (overwrite || File.Exists(filename))
     {
         File.WriteAllText(filename, j.ToString());
     }
 }
        static void Main(string[] args)
        {
            var j = new journal();

            j.AddEntery("Some string 1");
            j.AddEntery("Some string 2");

            Console.WriteLine(j);

            var    p        = new Persistence();
            string filename = @"journal.txt";

            p.SaveToFile(j, filename, true);
            Process.Start(filename);



            Console.WriteLine("Press <enter> to quit:");
            Console.Read();
        }