module ActionDispatch::Routing::Mapper::Resources

def nested(&block)
  unless resource_scope?
    raise ArgumentError, "can't use nested outside resource(s) scope"
  end
  with_scope_level(:nested) do
    if shallow? && shallow_nesting_depth >= 1
      shallow_scope do
        path_scope(parent_resource.nested_scope) do
          scope(nested_options, &block)
        end
      end
    else
      path_scope(parent_resource.nested_scope) do
        scope(nested_options, &block)
      end
    end
  end
end