title: Can't modify my SwiftyJSON object
body: <p>I have the variable</p>
  
  <pre><code>    static var DeliveryStatus: [String : JSON] =
      [
          "claimable": [],
          "onTime": [],
          "future": [],
          "claimDone": [],
          "tooOld": [],
      ]
  </code></pre>
  
  <p>In my fonction I try to append some data to claimable -> Json without success
  He told me it's an immutable value I don't understand why. 
  Here the code where I try to change my value</p>
  
  <pre><code>static func moreCard(status:String, newJson: JSON)
  {
      var json:JSON = JSON(DashboardManager.DeliveryStatus)
      for elem in newJson["cards"]
      {
          DeliveryStatus[status]?["cards"].array?.append(elem.1)
      }        
  }
  </code></pre>