title: Beego API Document swagger returns 404
body: <p>I am following this <a href="http://beego.me/blog/beego_api" rel="nofollow">blog</a> and <a href="https://www.youtube.com/watch?v=w7RziV_Sn-g" rel="nofollow">video</a> to do the API demo, when I visit </p>
  
  <pre><code>http://127.0.0.1:8080/swagger I can see the link
  
  /swagger-1/
  </code></pre>
  
  <p>but when I click it, It returns 404. Anyone knows about it?</p>