Rails route to only index
See Chapter 4.6 of the Rails Routing Guide.
By default, Rails creates routes for the seven default actions (index, show, new, create, edit, update, and destroy) for every RESTful route in your application. You can use the :only and :except options to fine-tune this behavior. The :only option tells Rails to create only the specified routes:
resources :photos, :only => [:index, :show]