title: Koa w/client side router
body: <p>Current situation:</p>
  
  <p>frontend: React &amp; React-Router</p>
  
  <p>backend: Koa</p>
  
  <pre><code>app.use(mount('/graphql', graphqlHTTP({ schema: schema })));
  app.use(mount('/api', api));
  app.use(serve(__dirname + '../../public')); //serves static index.html
  </code></pre>
  
  <p>When I click on React Router's &lt; Link > in the browser, every webpages shows.
  Whenever I refresh the page or manually enter a link. I get a 'not found' page. There is no server side rendering going here by the way. How do I let React-Router handle routes not specified above, i.e. only on the client?</p>