title: Namespace in rails routing
body: <p>First, why do we need to namespace controllers? </p>
  
  <p>The example on <a href="http://guides.rubyonrails.org/routing.html#controller-namespaces-and-routing" rel="nofollow">rails guides</a> shows</p>
  
  <pre><code>namespace :admin do
    resources :post, :comments
  end
  </code></pre>
  
  <p>In this case, we have paths such as GET /admin/posts. Is it identical to GET /posts? Or is GET /posts kept as original while another GET /admin/posts is added as extra?</p>
  
  <p>Does rails create any other stuff for namespace? </p>