title: React-ga not computing first access
body: <p>I have React-ga set up with React Router in the following manner:</p>
  
  <pre><code>...
  import { Router } from 'react-router-dom';
  import createHistory from 'history/createBrowserHistory';
  import {Provider} from 'react-redux';
  import ReactGA from 'react-ga';
  
  ReactGA.initialize('MY TRACKING CODE', {
    debug: true
  });
  
  const history = createHistory();
  history.listen((location) =&gt; {
    ReactGA.set({ page: location.pathname });
    ReactGA.pageview(location.pathname);
  });
  
  
  ReactDOM.render((
    &lt;Provider store={store}&gt;
      &lt;Router history={history}&gt;
        &lt;Layout /&gt;
      &lt;/Router&gt;
    &lt;/Provider&gt;
  ), document.getElementById('root'));
  registerServiceWorker();
  </code></pre>
  
  <p>if I'm already on the page and access another path, I get the following on the console:</p>
  
  <pre><code> log.js:2 [react-ga] called ga('set', fieldsObject);
   log.js:2 [react-ga] with fieldsObject: {"page":"/products"}
   log.js:2 [react-ga] called ga('send', 'pageview', path);
   log.js:2 [react-ga] with path: /products
  </code></pre>
  
  <p>However, if I access the page for the first time (by clicking on a link or typing the path directly on the browser), I don't get anything on the console.</p>
  
  <p>Is there any step that I'm missing in order to compute the first access?</p>