title: Swift NSUserDefaults setString:forKey:?
body: <p>NSUserDefaults has <code>integerForKey:</code>, <code>setInteger:forKey:</code> and <code>stringForKey:</code>, but does not have <code>setString:forKey:</code>.</p>
  
  <p>How do you set a string to NSUserDefaults? It has <code>setObject:forKey:</code> but, in Swift, String is a struct. Is it ok to use <code>setObject:forKey:</code> to store a string?</p>