     }
     
     internal func loadOrCreateInitialModel() {
-        
-        let url = NSURL.applicationDocumentsDirectory().URLByAppendingPathComponent(modelName)
-        if NSFileManager.defaultManager().fileExistsAtPath(url.path!) == false {
-            createInitialModelAtURL(url)
-        }
-        
-        guard let data = NSData(contentsOfURL: url) else {
+        if NSFileManager.defaultManager().fileExistsAtPath(modelURL.path!) == false {
+            createInitialModelAtURL(modelURL)
+        }
+        
+        guard let data = NSData(contentsOfURL: modelURL) else {
             fatalError("model data not found")
         }
         

            order += 1
        }
        
        let data = NSKeyedArchiver.archivedDataWithRootObject(passes)
        return data.writeToURL(url, atomically: true)
    }
    
    private lazy var dateFormatter: NSDateFormatter = {


typealias PassUpdatesFuture = Future<[Pass]>

class PassDataSource: NSObject {
    
    var orderedPasses: [Pass] {
