Ref: changed file and folder organization

src/environments/environment.prod.ts

@@ -0,0 +1,3 @@
+export const environment = {
+  production: true
+};

src/environments/environment.ts

@@ -0,0 +1,15 @@
+// This file can be replaced during build by using the `fileReplacements` array.
+// `ng build ---prod` replaces `environment.ts` with `environment.prod.ts`.
+// The list of file replacements can be found in `angular.json`.
+
+export const environment = {
+  production: false
+};
+
+/*
+ * In development mode, to ignore zone related error stack frames such as
+ * `zone.run`, `zoneDelegate.invokeTask` for easier debugging, you can
+ * import the following file, but please comment it out in production mode
+ * because it will have performance impact when throw error
+ */
+// import 'zone.js/dist/zone-error';  // Included with Angular CLI.