module ActionDispatch::Routing::Mapper::Resources

def collection(&block)

`search_photos_url` and `search_photos_path` route helpers.
and route to the search action of `PhotosController`. It will also create the
This will enable Rails to recognize paths such as `/photos/search` with GET,

end
end
get 'search'
collection do
resources :photos do

To add a route to the collection: 
def collection(&block)
  unless resource_scope?
    raise ArgumentError, "can't use collection outside resource(s) scope"
  end
  with_scope_level(:collection) do
    path_scope(parent_resource.collection_scope, &block)
  end
end