Add Gist example and fix /about bug. Closes #6

pages/about.js

@@ -17,7 +17,7 @@ export default () => (
         <p className="mb1 mt2">There are a few different ways to import code into Carbon:</p>
         <ul className="mt0 mb3">
           <li>Drag a file into the editor</li>
-          <li>Append a GitHub gist id to the url (<a className="link" href="#">example</a>)</li>
+          <li>Append a GitHub gist id to the url (<a className="link" href="/0db00e81d5416c339181e59481c74b59">example</a>)</li>
           <li>Paste your code directly</li>
         </ul>
         <h4 className="mb0">Customization</h4>

server.js

@@ -20,6 +20,9 @@ app.prepare()
 
   server.use(morgan('tiny'))
 
+  server.get('/about', (req, res) =>
+    app.render(req, res, '/about'))
+
   // if root, render webpage from next
   server.get('*', (req, res) =>
     app.render(req, res, '/', req.query))