i am building an ios app in swift and when i enter a number this happens : on this line of code i get this error 
    if diceRoll == userGuessTextField.text {

2016-02-04 18:38:34.756 How Many Fingers[2972:158461] Can't find keyplane that supports type 4 for keyboard iPhone-PortraitChoco-NumberPad; using 1336863583_PortraitChoco_iPhone-Simple-Pad_Default
fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb) 

import UIKit

class ViewController: UIViewController {

    @IBOutlet var userGuessTextField: UITextField!
    
    @IBOutlet var resultLabel: UILabel!
    
    @IBAction func guess(sender: AnyObject) {
    
    let diceRoll = String(arc4random_uniform(6))
   
        
        if diceRoll == userGuessTextField.text {
            

            resultLabel.text = "You're right!"
        }
        else {
         
            resultLabel.text = "Wrong! It was a " + diceRoll
        }
    }

    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }[enter image description here][1]


  [1]: http://i.stack.imgur.com/Y8slL.png