Add Bootstrap JS to make collapsible nav work

This example uses the collapsible nav for smaller screen sizes, and it
requires Bootstrap JS to get that functionality.

jumbotron/index.html

@@ -91,5 +91,7 @@
 
     </div> <!-- /container -->
 
+    <script src="../assets/js/jquery.js"></script>
+    <script src="../bootstrap/js/bootstrap.min.js"></script>
   </body>
 </html>
\ No newline at end of file