title: ng-bootstrap not working in angular 4
body: <p>I am new with angular 4, I am trying to configure bootstrap.
  I installed ng-bootstrap:</p>
  
  <p><a href="https://ng-bootstrap.github.io/#/getting-started" rel="noreferrer">https://ng-bootstrap.github.io/#/getting-started</a></p>
  
  <p>I did all like on the page, but I don't see the bootstrap on my page.
  Here is my code:</p>
  
  <p>src/app/app.module.ts</p>
  
  <pre><code>import { BrowserModule } from '@angular/platform-browser';
  import { NgModule } from '@angular/core';
  
  import { AppComponent } from './app.component';
  import { FormsModule } from '@angular/forms';
  import {NgbModule} from '@ng-bootstrap/ng-bootstrap';
  
  @NgModule({
    declarations: [
      AppComponent
    ],
  imports: [
     BrowserModule,
     FormsModule,  // add  this
     NgbModule.forRoot()
  ],
  providers: [],
  bootstrap: [AppComponent]
  })
  export class AppModule { }
  </code></pre>
  
  <p>src/app/app.component.html</p>
  
  <pre><code>&lt;div class="container"&gt;
  
  &lt;h1 class="text-primary"&gt;{{title}} &lt;/h1&gt;
  
  &lt;h2 class="text-primary"&gt;My Heroes&lt;/h2&gt;
  &lt;ul class="heroes"&gt;
    &lt;li *ngFor="let hero of heroes"
      [class.selected]="hero === selectedHero"
      (click)="onSelect(hero)"&gt;
      &lt;span class="badge"&gt;{{hero.id}}&lt;/span&gt; {{hero.name}}
     &lt;/li&gt;
  &lt;/ul&gt;
  
  &lt;div class="alert alert-success" role="alert"&gt;
   &lt;strong&gt;Well done!&lt;/strong&gt; You successfully read this important alert 
     message.
  &lt;/div&gt;
  
  &lt;div *ngIf="selectedHero"&gt;
    &lt;h2&gt;{{selectedHero.name}} details!&lt;/h2&gt;
  &lt;div&gt;&lt;label&gt;id: &lt;/label&gt;{{selectedHero.id}}&lt;/div&gt;
  &lt;div&gt;
    &lt;label&gt;name: &lt;/label&gt;
    &lt;input [(ngModel)]="selectedHero.name" placeholder="name"/&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p></p>
  
  <p></p>
  
  <p>I tried also some code in the index.html, but it does not work, </p>
  
  <p>for this line I am expecting to see some color:</p>
  
  <pre><code>&lt;h1 class="text-primary"&gt;{{title}} &lt;/h1&gt;
  </code></pre>
  
  <p>I don't find any reference of bootstrap when I check the header of the html.
  Any help, please?
  Thanks</p>