title: swaggo: getting Failed to fetch doc.json
body: <p>I used swag inti
  and then registered it with
  <code>r.GET("/swagger/*any", ginSwagger.WrapHandler(swaggerFiles.Handler))</code>
  But when I start swagger with <a href="http://localhost:3000/swagger/index.html" rel="nofollow noreferrer">this</a>,</p>
  
  <p>I am getting</p>
  
  <p>Errors</p>
  
  <p>Fetch error</p>
  
  <p>Failed to fetch doc.json</p>
  
  <p>Environment</p>
  
  <p>swagger version: 2.0.0</p>
  
  <p>go version: 1.6.*</p>
  
  <p>OS: Mac</p>