title: Cannot GET / in simple vue setup
body: <p>So I try to set up a simple vue project. Webpack is able to compile, but not able to serve home page. Here is the repo: </p>
  
  <p><a href="https://github.com/kenpeter/auto_complete_vue" rel="nofollow noreferrer">https://github.com/kenpeter/auto_complete_vue</a></p>
  
  <pre><code>npm run dev
  </code></pre>
  
  <p>Error I got is </p>
  
  <pre><code>Cannot GET /
  </code></pre>
  
  <p>Based on this template: </p>
  
  <p><a href="https://github.com/vuejs-templates/webpack-simple" rel="nofollow noreferrer">https://github.com/vuejs-templates/webpack-simple</a></p>