app.component.ts

<app-navbar></app-navbar> 
<div class="container">
    <div class="starter-template">
        <h1>Angular, Bootstrap & Firebase Starter Application</h1>
        <p class="lead">This application is built with Angular 4, Bootstrap 4 and Firebase.</p>
        <h3>Courses List</h3>
        <courses-list></courses-list>
    </div>
</div>