如何将斜角添加到UITableViewCell

import UIKit

class SlopedView: UIView {
    override func drawRect(rect: CGRect) {
        let path = UIBezierPath()
        path.moveToPoint(CGPoint(x: rect.width, y: 0))
        path.addLineToPoint(CGPoint(x: rect.width, y: rect.height))
        path.addLineToPoint(CGPoint(x: 0, y: rect.height))
        path.addLineToPoint(CGPoint(x: 0, y: 0))
        path.closePath()
        
        let diagonalPath = UIBezierPath()
        diagonalPath.moveToPoint(CGPoint(x: 0, y: 0))
        diagonalPath.addLineToPoint(CGPoint(x: rect.width, y: rect.height))
        diagonalPath.closePath()
        
        path.appendPath(diagonalPath)
        UIColor.redColor().setFill()
        path.fill()
    }
}

class CustomTableViewCell: UITableViewCell {
    let slopedView = SlopedView()
    
    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        
        slopedView.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
        contentView.addSubview(slopedView)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class ViewController: UITableViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.registerClass(CustomTableViewCell.self, forCellReuseIdentifier: "CustomCell")
    }
    
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("CustomCell", forIndexPath: indexPath) as! CustomTableViewCell
        return cell
    }
}