// this method will change the current view to next view
- (IBAction)startButtonPressed:(id)sender
{
    //next view controllers
    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
        tutorialViewController = [[TutorialViewController alloc]initWithNibName:@"TutorialView_iPad" bundle:nil];
        notesViewController = [[NoteViewController alloc]initWithNibName:@"NoteView_iPad" bundle:nil];
    }
    else {
        tutorialViewController = [[TutorialViewController alloc]initWithNibName:@"TutorialView" bundle:nil];
        notesViewController = [[NoteViewController alloc]initWithNibName:@"NoteView" bundle:nil];
    }
    tutorialViewController.title = @"Index";
    //navigation logic
    UINavigationController *tutorialNavigation = [[[UINavigationController alloc]initWithRootViewController:tutorialViewController ]autorelease];
    tutorialNavigation.navigationBar.tintColor = [UIColor blackColor];
    notesViewController.title = @"Notes";
    UINavigationController *notesNavigation = [[[UINavigationController alloc]initWithRootViewController:notesViewController]autorelease];
    notesNavigation.navigationBar.tintColor = [UIColor blackColor];
    //adding view controllers to tab bar controller with navigation controller
    tabBarController = [[UITabBarController alloc]initWithNibName:nil bundle:nil];
    tabBarController.viewControllers = [NSArray arrayWithObjects:tutorialNavigation,notesNavigation,nil];
    tabBarController.selectedViewController = tutorialNavigation;
    //flip animation
    tabBarController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
    [self presentModalViewController:tabBarController animated:YES];
    //[self presentViewController:tabBarController animated:YES completion:nil];
}