How can I sort an array of weekday strings?

I start out with:

var weekdays = ["Sunday", "Friday", "Tuesday"]

I need it changed to:

weekdays = ["Sunday", "Tuesday", "Friday"]

I've converted them to Ints:

var days = [Int]()

for day in weekdays {

    let formatterWeekday = NSDateFormatter()

    formatterWeekday.dateFormat = "e"

    let weekday = formatterWeekday.dateFromString(day)

    let weekdayString = formatterWeekday.stringFromDate(weekday!)

    let dayInt = Int(weekdayString)

    days.append(dayInt!)

}

days.sortInPlace()

Which then gives me:

days = [1,3,6]

So then how do I convert Ints to weekday strings?