ContactsController ES6 refactoring

src/client/controllers/ContactsController.js

@@ -1,7 +1,7 @@
-module.exports = function (app) {
-    app.controller('ContactsController', function ($scope, config) {
+export default function (app) {
+    app.controller('ContactsController', ($scope, config) => {
         $scope.address = config.address;
         $scope.telephone = config.telephone;
         $scope.email = config.email;
     });
-};
+};