title: Using React IndexRoute in react-router v4
body: <p>I'm learning React myself with online tutorial.</p>
  
  <p>So this is a basic example about using React Router: </p>
  
  <pre><code>&lt;Router history={browserHistory}&gt;
    &lt;Route path="/" component={App}&gt;
      &lt;IndexRoute component={Home}/&gt;
      &lt;Route path="/home" component={Home}/&gt;
      &lt;Route path="/about" component={About}/&gt;
      &lt;Route path="/contact" component={Contact}/&gt;
    &lt;/Route&gt;
  &lt;/Router&gt;
  </code></pre>
  
  <p>With my App component:</p>
  
  <pre><code>class App extends React.Component {
     render() {
        return (
           &lt;div&gt;
              &lt;ul&gt;
                &lt;li&gt;&lt;Link to="home"&gt;Home&lt;/Link&gt;&lt;/li&gt;
                &lt;li&gt;&lt;Link to="about"&gt;About&lt;/Link&gt;&lt;/li&gt;
                &lt;li&gt;&lt;Link to="contact"&gt;Contact&lt;/Link&gt;&lt;/li&gt;
             &lt;/ul&gt;
            {this.props.children}
          &lt;/div&gt;
       )
     }
  }
  export default App;
  </code></pre>
  
  <p>However, I have problem when using IndexRoute because it shows nothing, so I search for the module of react-router-dom v4 on npm and there is no IndexRoute inside.
  Instead it uses this:</p>
  
  <pre><code>&lt;Router&gt;
    &lt;div&gt;
    &lt;ul&gt;
      &lt;li&gt;&lt;Link to="/"&gt;Home&lt;/Link&gt;&lt;/li&gt;
      &lt;li&gt;&lt;Link to="/about"&gt;About&lt;/Link&gt;&lt;/li&gt;
      &lt;li&gt;&lt;Link to="/contact"&gt;Contact&lt;/Link&gt;&lt;/li&gt;
    &lt;/ul&gt;
    &lt;hr/&gt;
    &lt;Route exact path="/" component={Home}/&gt;
    &lt;Route path="/about" component={About}/&gt;
    &lt;Route path="/contact" component={Contact}/&gt;
    &lt;/div&gt;
  &lt;/Router&gt;
  </code></pre>
  
  <p>So how can I render 2 component for 1 path ?</p>