added documentation

README.md

-## Hi, this project very much requires the maintainer, if you have a chewing and appropriate skills, please [contact me](mailto:ibn@rubaxa.org?subject=Sortable%20vs.%20Maintainer)!
-
----
-
 # Sortable
 Sortable is a <s>minimalist</s> JavaScript library for reorderable drag-and-drop lists.
 
@@ -109,6 +105,7 @@ var sortable = new Sortable(el, {
 	scrollFn: function(offsetX, offsetY, originalEvent, touchEvt, hoverTargetEl) { ... }, // if you have custom scrollbar scrollFn may be used for autoscrolling
 	scrollSensitivity: 30, // px, how near the mouse must be to an edge to start scrolling.
 	scrollSpeed: 10, // px
+	bubbleScroll: true, // apply autoscroll to all parent elements, allowing for easier movement
 
 	setData: function (/** DataTransfer */dataTransfer, /** HTMLElement*/dragEl) {
 		dataTransfer.setData('Text', dragEl.textContent); // `dataTransfer` object of HTML5 DragEvent
@@ -408,6 +405,14 @@ The speed at which the window should scroll once the mouse pointer gets within t
 ---
 
 
+#### `bubbleScroll` option
+If set to `true`, the normal `autoscroll` function will also be applied to all parent elements of the element the user is dragging over.
+
+Demo: https://jsbin.com/kesewor/edit?html,js,output
+
+
+---
+
 ### Event object ([demo](http://jsbin.com/xedusu/edit?js,output))
 
  - to:`HTMLElement` — list, in which moved element.