title: how to map root to a resource in rails?
body: <p>I got a resource called posts, now i want to map root to posts as a resource.
  so as the result:</p>
  
  <p>'/posts' => nothing</p>
  
  <p>'/posts/1' => nothing</p>
  
  <p>but</p>
  
  <p>'/' => posts#index</p>
  
  <p>'/1' => posts#show</p>