title: first mac app - push viewcontroller
body: <p>I have a question, I do some iphone application and now I want to do a little mac application.</p>
  
  <p>From a clean application I add a button on MainMenu xib, than I add a NSViewController to MainMenu (from IB) with one Action.
  I create a new NSViewController (FirstViewController) with a nib file and a button.
  Now I want only to create a function to push FirstController from MainMenu and a simple function to push MainMenu from FirstController.</p>
  
  <p>something like this</p>
  
  <pre><code>ViewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:[NSBundle mainBundle]];
  [self.navigationController pushViewController: ViewController animated:YES];
  </code></pre>
  
  <p>How can I do it???</p>