title: Add a tap gesture to a part of a UILabel
body: <p>I have a NSAttributedString like so:</p>
  
  <pre><code>NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:@"testing it out @clickhere"];
  NSInteger length = str.length;
  [str addAttribute:NSForegroundColorAttributeName value:[UIColor bestTextColor] range:NSMakeRange(0,length)];
  </code></pre>
  
  <p>The NSMutableAttributedString gets set to a UILabel like so:</p>
  
  <pre><code>label.attributedText = str;
  </code></pre>
  
  <p>How do I make a tap gesture (or something clickable) to another viewcontroller for the words '@clickhere in the string above?</p>
  
  <p>Thanks!</p>