docs(forms): add radio button examples (#11676)

modules/@angular/examples/forms/ts/reactiveRadioButtons/module.ts

@@ -0,0 +1,20 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {NgModule} from '@angular/core';
+import {ReactiveFormsModule} from '@angular/forms';
+import {BrowserModule} from '@angular/platform-browser';
+import {ReactiveRadioButtonComp} from './reactive_radio_button_example';
+
+@NgModule({
+  imports: [BrowserModule, ReactiveFormsModule],
+  declarations: [ReactiveRadioButtonComp],
+  bootstrap: [ReactiveRadioButtonComp]
+})
+export class AppModule {
+}