title: How to set an optional parameter on root route in react-router v4?
body: <p>Let's say I have the following 2 routes:</p>
  
  <pre><code>    ...
      &lt;Route exact path="/:param1?/" component={Home}/&gt;
      &lt;Route path="/news" component={News}/&gt;
      ...
  </code></pre>
  
  <p>now when I try to hit route <code>/news</code> the root route for <code>Home</code> with the parameter <code>param1</code> is triggered...</p>
  
  <p>I assume the solution would be to set a questionmark before the param1 like this <code>/?param1</code> so it can be held appart from the routes, but I can not figure out how to do this in react-router v4</p>