title: Versioning API duplication
body: <p>In my Ruby on Rails application I have my api routes looks like this:</p>
  
  <pre><code>namespace :api, defaults: { format: :json }  do
    namespace :v1 do
      resources :users
      resources :clients
    end
  end
  </code></pre>
  
  <p>Now my response format for <code>users</code> resource will change so I want to create new api version: v2. My <code>clients</code> resource will not change, so I need to copy <code>jbuilder</code> templates and controllers to <code>v2</code> api namespace. This will be a duplication. Is there way to avoid that? Let say whenever someone tries to reach <code>api/v2/clients/*</code> I will redirect him to <code>api/v1/clients*</code></p>