Rounded square button in swift ( customizing shape and color in code)

override func viewDidLoad() {

        super.viewDidLoad()

     let TAG_BTN = 1001  // it is assigned to button which you want to change properties.

     let btn : UIButton  = self.view.viewWithTag(TAG_BTN) as! UIButton

     btn.layer.cornerRadius = 5

     btn.layer.borderColor = UIColor.grayColor().CGColor

     btn.layer.borderWidth = 1.5

     btn.backgroundColor = UIColor(red: 1.0, green: 0, blue: 0, alpha: 1)

}