scrollview使用snapkit约束

使用storyboard及纯代码Snapkit使用scrollview:
https://www.jianshu.com/p/48257d054d06

使用代码约束：

        self.scrollView.addSubview(self.loginView)
        self.scrollView.addSubview(self.registerView)
        
        self.loginView.snp.makeConstraints { (make) in
            make.left.top.bottom.equalTo(self.scrollView)
            make.width.equalTo(SCREEN_WIDTH)
            make.height.equalTo(self.scrollView.snp.height)
        }
        
        self.registerView.snp.makeConstraints { (make) in
            make.right.top.bottom.equalTo(self.scrollView)
            make.left.equalTo(self.loginView.snp.right)
            make.width.height.equalTo(self.loginView)
        }