Add drag and drop to structure side_bar

app/assets/javascripts/site_editor.js

@@ -5,6 +5,9 @@
 // the compiled file.
 //
 //= require jquery
+//= require jquery.ui.draggable
+//= require jquery.ui.droppable
+//= require jquery.ui.sortable
 //= require jquery_ujs
 //= require bootstrap
 //= require jquery.isotope.min
@@ -14,4 +17,5 @@
 //= require side_bar_history
 //= require page_edit
 //= require tinymce-jquery
-//= require tinymce_orbit
+//= require tinymce_orbit
+//= require lib/jquery.ui.nestedSortable.js