title: 'stringByAppendingPathComponent' is unavailable
body: <p>I'm getting the error</p>
  
  <pre><code>'stringByAppendingPathComponent' is unavailable: Use 'stringByAppendingPathComponent' on NSString instead.
  </code></pre>
  
  <p>when I try to do </p>
  
  <pre><code>let documentsFolder = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
  let databasePath = documentsFolder.stringByAppendingPathComponent("test.sqlite")
  </code></pre>
  
  <p>This apparently worked for people before, but it doesn't work for me now in Xcode 7 beta 5.</p>
  
  <p><a href="https://forums.developer.apple.com/thread/13580">This thread</a> on the Apple Developer Forums had the suggestion to use an extension or do a direct cast to <code>NSString</code>. But if I do convert it to an <code>NSString</code> </p>
  
  <pre><code>let databasePath = documentsFolder.stringByAppendingPathComponent("test.sqlite" as NSString)
  </code></pre>
  
  <p>then I get the error</p>
  
  <pre><code>'NSString' is not implicitly convertible to 'String'...
  </code></pre>
  
  <p>and it gives me the option to "fix-it" by inserting <code>as String</code>, which brings us back to the original error.</p>
  
  <p>This also happens for <code>stringByAppendingPathExtension</code>.</p>
  
  <p>What do I do?</p>