iOS App Dev Error. "terminate called throwing an exception"

//
//  main.m
//  Crystal Ball
//
//  Created by Logan Shire on 12/28/12.
//
//

#import <UIKit/UIKit.h>

#import "AppDelegate.h"

int main(int argc, char *argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
    }
}

Here is my new header code:

//
//  ViewController.h
//  Crystal Ball
//
//  Created by Logan Shire on 12/28/12.
//
//

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController
- (IBAction)buttonPressed:(id)sender;
@property (strong, nonatomic) IBOutlet UILabel *predictionLabel;

@end

And my new main code:


//
//  ViewController.m
//  Crystal Ball
//
//  Created by Logan Shire on 12/28/12.
//
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)buttonPressed:(id)sender {
    self.predictionLabel.text = @"Definitely yes";
}
@end