Merge pull request #123 from thgreasi/master

Emphasize ng-model and ng-repeat's model, index matching requirement.

Author: thgreasi

README.md

@@ -34,6 +34,7 @@ Apply the directive to your form elements:
 * `ng-model` is required, so that the directive knows which model to update.
 * `ui-sortable` element should only contain one `ng-repeat` and not any other elements (above or below).  
   Otherwise the index matching of the generated DOM elements and the `ng-model`'s items will break.
+  **In other words: The items of `ng-model` must match the indexes of the genretated DOM elements.**
 * `ui-sortable` lists containing many 'types' of items can be implemented by using [dynamic template loading with ng-include](http://stackoverflow.com/questions/14607879/angularjs-load-dynamic-template-html-within-directive/14621927#14621927), to determine how each model item should be rendered.
 
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