title: Adding prefix to a named route helper under namespace
body: <p>This is how a common namespace looks like.</p>
  
  <pre><code>namespace :admin do
    resources :posts
  end
  </code></pre>
  
  <p>And it creates a named route like this one;</p>
  
  <pre><code>new_admin_post_path
  </code></pre>
  
  <p>Here's my question; how can I add a prefix (like "new" in this example) to a named route under namespace?</p>
  
  <p>Let's say my route definition likes this one;</p>
  
  <pre><code>namespace :admin do
    get 'post/new' =&gt; 'posts#new', as: 'post'
  end
  </code></pre>
  
  <p>And it's creates a named route like;</p>
  
  <pre><code>admin_post_path
  </code></pre>
  
  <p>I want to add "new" prefix to this named route and make it look like <code>new_admin_post_path</code> and I don't want to use <code>resources</code>.</p>