[BUGFIX] correct path

app/templates/_index.html

@@ -20,7 +20,7 @@
 <!-- Add your site or application content here -->
 <p>Hello world! This is HTML5 Boilerplate.</p>
 
-<script src="js/main.js"></script>
+<script src="main.js"></script>
 
 <!-- Google Analytics: change UA-XXXXX-X to be your site's ID. -->
 <script>