gistfile1.m

- (void)viewDidLoad {
    ChildViewController *cvc = [self.storyboard instantiateViewControllerWithIdentifier:@"ChildViewController"];

    [super viewDidLoad];
    [self addChildViewController:cvc];
    cvc.view.frame = self.containerView.bounds;
    [self.containerView addSubview:cvc.view];
    [cvc didMoveToParentViewController:self];
}