更新ボタンを押すとニュースを読み込むアプリを作っているのですが、アプリを開いた瞬間にニュースを読み込むようにするにはどのようにすればいいのでしょうか

import UIKit

class ViewController: UITableViewController {

    var entries = NSMutableArray()

    let newsUrlStrings = [
        "http://ajax.googleapis.com/ajax/services/feed/load?v=1.0&q=http://www3.nhk.or.jp/rss/news/cat0.xml&num=8",
        "http://ajax.googleapis.com/ajax/services/feed/load?v=1.0&q=http://www3.nhk.or.jp/rss/news/cat6.xml&num=8",
        "http://ajax.googleapis.com/ajax/services/feed/load?v=1.0&q=http://www3.nhk.or.jp/rss/news/cat7.xml&num=8"
        ]

    let imageNames = [
    "japan.jpg",
    "world.jpg",
    "sport.jpg",
    ]

    @IBAction func refresh(sender: AnyObject) {
        entries.removeAllObjects()


        for newsUrlString in newsUrlStrings{

            var url = NSURL(string: newsUrlString)!
            var task = NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: { data, respinse, error in

                var dict = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as! NSDictionary

                if var responseData = dict["responseData"] as? NSDictionary {
                    if var feed = responseData["feed"] as? NSDictionary {
                        if var entries = feed["entries"] as? NSArray {

                            var formatter = NSDateFormatter()
                            formatter.locale = NSLocale(localeIdentifier: "en-US")
                            formatter.dateFormat = "EEE, dd MMMM yyyy HH:mm:ss zzzz"

                            for var i = 0; i < entries.count; i++ {
                                var entry = entries[i] as! NSMutableDictionary

                                entry["url"] = newsUrlString

                                var dateStr = entry["publishedDate"] as! String
                                var date = formatter.dateFromString(dateStr)
                                entry["date"] = date
                            }

                            self.entries.addObjectsFromArray(entries as[AnyObject])

                            self.entries.sortUsingComparator({ object1, object2 in

                            var date1 = object1["date"] as! NSDate
                            var date2 = object2["date"] as! NSDate

                            var order = date1.compare(date2)

                                if order == NSComparisonResult.OrderedAscending {
                                    return NSComparisonResult.OrderedAscending
                                }
                                else if order == NSComparisonResult.OrderedAscending{
                                    return NSComparisonResult.OrderedAscending
                                }

                                return order
                            })
                        }
                    }
                }



                dispatch_async(dispatch_get_main_queue(),{

                    self.tableView.reloadData()

                    })
                })


            task.resume()
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    override func tableView(tableView: UITableView, numberOfRowsInSection
        section: Int) -> Int {
        return entries.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath
        indexPath: NSIndexPath) -> UITableViewCell {

        var cell = tableView.dequeueReusableCellWithIdentifier("news") as! UITableViewCell

        var entry = entries[indexPath.row] as! NSDictionary

        var titleLabel = cell.viewWithTag(1) as! UILabel
        titleLabel.text = entry["title"] as? String

        var descriptionLabel = cell.viewWithTag(2) as! UILabel
        descriptionLabel.text = entry["contentSnippet"] as? String

        var urlString = entry["url"] as! String
        var index = find(newsUrlStrings, urlString)
        var imageName = imageNames[index!]
        var image = UIImage(named: imageName)

        var imageView = cell.viewWithTag(4) as! UIImageView
        imageView.image = image
        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        performSegueWithIdentifier("detail", sender: entries[indexPath.row])
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?){
        if segue.identifier == "detail" {
            var detailController = segue.destinationViewController as! DetailController

                    detailController.entry = sender as! NSDictionary
                }
            }
}

こうなっています。
タイトルの通り、アプリを開いた瞬間にニュース記事を読み込みたいとき、どうすればいよいのでしょうか