Please try this code in swift,
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
   // let the controller to know that able to edit tableView's row 
   return true
}
override func tableView(tableView: UITableView, commitEditingStyle editingStyle UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath)  {
   // if you want to apply with iOS 8 or earlier version you must add this function too. (just left in blank code)
}
override func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]?  {
   // add the action button you want to show when swiping on tableView's cell , in this case add the delete button.
   let deleteAction = UITableViewRowAction(style: .Default, title: "Delete", handler: { (action , indexPath) -> Void in
   // Your delete code here.....
   .........
   .........
   })
   // You can set its properties like normal button
   deleteAction.backgroundColor = UIColor.redColor()
   return [deleteAction]
}