some helpers for resources route
Defining Multiple Resources at the Same Time
Singular Resources

RailsGUides says this will create six different routes in your application
but I see that create seven different routes too through rake routes
It's has another route:
geocoder_index   GET  /geocoder(.:format)   geocoder#index
namespace and routing
scope module: and routing

route /posts (without the prefix /admin) to Admin::PostsController
scope and routing

route /admin/posts to PostsController (without the Admin:: module prefix)
a single case
Nested routes
Resources should never be nested more than 1 level deep.
Shallow Nesting
scope shallow_path  and  scope shallow_prefix
Routing Concerns
some more RESTful actions
some Non-Resourceful Routes
Customizing Resourceful Routes
Inspecting and Testing Routes
Merge pull request #7 from hxx/Rails-Routing-from-the-Outside-In

Rails routing from the outside in