title: How to implement Game Center in iOS app?
body: <p>I am a bit confused now. I read through a lot articles that describe how to implement game center. All of them mention that I have to create an app at itunes connect first.</p>
  
  <p><strong>So do I have to submit my app to iTunes first? Why do I have to do that? Do I have to set a later release date than?</strong></p>
  
  <p>All suggestions appreciated!</p>