private void AddTaskButton_Click(object sender, RoutedEventArgs e)
        {
            AddTask addTask = new AddTask
            {
                Owner = this
            };

            if (addTask.ShowDialog() == true)
            {
                RadioButton radio = addTask.GroupBox.Children.OfType <RadioButton>().FirstOrDefault(r => r.IsChecked == true);
                int         ww    = Int32.Parse(radio.Tag.ToString());
                Importance  imp   = (Importance)ww;
                Task        task  = new Task((Category)addTask.CategoryComboBox.SelectedItem, false, (String)addTask.CreationDate.Content, addTask.date, imp, addTask.Steps);
                Tasks.Add(task);
                db.AddTask(task);
            }
        }