title: Detecting when a button is touched in SKScene?
body: <p>I created a storyboard and added a scene with two buttons. I cannot figure out how to know when a button is pressed on my GameScene.swift class.</p>
  
  <p>How can this be done?</p>
  
  <p><img src="https://i.stack.imgur.com/bV0wq.png" alt="enter image description here"></p>