Programmatically create UIStackView

stack.swift

lazy var v1:UIView = {
        let v = UIView()
        v.backgroundColor = .blueColor()
        return v
}()
    
lazy var v2:UIView = {
        let v = UIView()
        v.backgroundColor = .blueColor()
        return v
}()
    
lazy var stack:UIStackView = {
        let s = UIStackView(frame: self.view.bounds)
        s.axis = .Vertical
        s.distribution = .FillEqually
        s.alignment = .Fill
        s.spacing = 5
        s.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
        
        s.addArrangedSubview(self.v1)
        s.addArrangedSubview(self.v2)

        return s
}()