ViewController.swift

import UIKit

let feedCellId = "feedCellId"

class FeedViewController: UICollectionViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.collectionView!.backgroundColor = UIColor.whiteColor()
        self.collectionView?.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: feedCellId)
    }
    
    override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }
    
    override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(feedCellId, forIndexPath: indexPath)
        
        return cell
    }
}