title: Get a Enum with a string in Swift
body: <p>I want to get the value from an enum after the user selected 'action' in a picker view.
  So I have as string: <code>selectedGenre = "action"</code>. </p>
  
  <p>How can I get "28" from the case?</p>
  
  <pre><code>public enum MovieGenres: String {
    case action = "28"
    case adventure = "12"
    case animation = "16"
    ...
  }
  </code></pre>
  
  <p>I need to have something like this:
  MoveGenres.("selectedgenre").rawValue</p>