Slide works, but shows a black screen

Hi guys, I'm new in swift dev.

I'm trying use this amazing lib, but I can't.



My storyboard:

My appdelegate.swift:

```
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.

let windowSizes = UIScreen.mainScreen().bounds

var leftViewController: UIViewController = UIViewController()
leftViewController.view.frame = CGRectMake(0, 0, 300.0, windowSizes.size.width)
leftViewController.view.backgroundColor = UIColor(hexString: "#FF0000")

var mainViewController = NavigationViewController()

// MARK: Side Menu
let slideMenuController = SlideMenuController(mainViewController: mainViewController, leftMenuViewController: leftViewController)
self.window?.rootViewController = slideMenuController
self.window?.makeKeyAndVisible()

return true
}
```

My folder structure:

What am I doing wrong? How I said, I'm new in iOS dev. Thanks!