The trick really is to bind the checkboxes for items to their flags. This way they get updated and you
don't need to have a ng-click method for each item. Rather then use ng-check on the items I used ng-model. 

Related Blog Posts:
https://anthonyfassett.blogspot.com/2015/01/array-valued-url-queries.html
https://anthonyfassett.blogspot.com/2014/11/angularjs-facets-for-search-grid.html