如何使标题单元格与Swift 2.0中的tableview单元一起移动

I am trying to create a tableview which starts the header in the middle of the tableview and then can be scrolled up with the added tableView Cells to the top then stops, and then the tableview cells can just scroll "under" it. I got the header to be in the middle of the tableview, but the tableView Cells just scroll on top of it, and the header doesnt really scroll to the top. it just stay where it is. I want to be able to let the header move as you scroll the list, and then stops when it reaches the top of the list, and then its just the tableView Cells that are moving afterwards.I am trying to create a tableview which starts