title: What exactly is init coder aDecoder?
body: <p>I'm learning iOS development from an online course and everytime I make a custom view (custom table view cell, collection view cell, etc) the instructor always implements this initializer:</p>
  
  <pre><code>required init?(coder aDecoder: NSCoder) {
      super.init(coder: aDecoder)
  }
  </code></pre>
  
  <p>Why exactly do I always have to call this? What does it do? Can I put properties inside the init?</p>