title: SIGABRT Error When I Sending Data to Kinvey
body: <p>Why does my data is not send to the Kinvey backend? My app keeps crashing and I get the <code>SIGABRT</code> error. I have tried changing the <code>String</code> to <code>NSString</code> but that didn't help. For some reason, my dashboard in Kinvey does show API Calls and Data storage but it's not storing anything (I am a beginner).</p>
  
  <pre><code>import UIKit
  
  class ReservationViewController: UIViewController {
  
      @IBOutlet weak var userName: UITextField!
      @IBOutlet weak var userEmail: UITextField!
      @IBOutlet weak var userSeat: UITextField!
      @IBOutlet weak var userDateTime: UIDatePicker!
  
      @IBAction func sendReservation(sender: AnyObject) {
          // STORE DATA
          let store = KCSAppdataStore.storeWithOptions([
              KCSStoreKeyCollectionName : "userReservation",
              KCSStoreKeyCollectionTemplateClass : Booking.self
          ])
          let reservation = Booking()
          reservation.name = userName.text
          reservation.email = userEmail.text
          reservation.seats = userSeat.text
          reservation.date = NSDate(timeIntervalSince1970: 1352149171) //sample date
          store.saveObject(
              reservation,
              withCompletionBlock: { (objectsOrNil: [AnyObject]!, errorOrNil: NSError!) -&gt; Void in
                  if errorOrNil != nil {
                      //save failed
                      NSLog("Save failed, with error: %@", errorOrNil.localizedFailureReason!)
                  } else {
                      //save was successful
                      NSLog("Successfully saved event (id='%@').", (objectsOrNil[0] as! NSObject).kinveyObjectId())
                  }
              },
              withProgressBlock: nil
          )
      }
  
      class Booking : NSObject {    //all NSObjects in Kinvey implicitly implement KCSPersistable
          var entityId: String? //Kinvey entity _id
          var name: NSString?
          var email: NSString?
          var seats: NSString?
          var date: NSDate?
  
      }
  
      override func hostToKinveyPropertyMapping() -&gt; [NSObject : AnyObject]! {
          return [
              "entityId" : KCSEntityKeyId, //the required _id field
              "name" : "name",
              "email" : "email",
              "seats" : "seats",
              "date" : "date",
          ]
      }
  
  
      override func viewDidLoad() {
          super.viewDidLoad()
  
          // Do any additional setup after loading the view.
      }
  
      override func didReceiveMemoryWarning() {
          super.didReceiveMemoryWarning()
          // Dispose of any resources that can be recreated.
      }
  }
  </code></pre>