Refactors most controllers and directives into classes for more organized and maintainable code

app/assets/javascripts/directives/functional/file-change.js

@@ -0,0 +1,16 @@
+/* @ngInject */
+export function fileChange() {
+  return {
+    restrict: 'A',
+    scope: {
+      handler: '&'
+    },
+    link: function(scope, element) {
+      element.on('change', function(event) {
+        scope.$apply(function() {
+          scope.handler({ files: event.target.files });
+        });
+      });
+    }
+  };
+}