How to set up routing in Rails?

Question

Ruby on Rails

Hello everybody.
There was a need to make url's of the following form: example.com/category_name/post_name
I wrote the following in the routes.rb file:

resources :categories do
    resources :posts
end

But such parameters give such URLs: example.com/categories/category_name/post_name
Question: how to remove the extra word categories in the URL? Defining all routes manually (not through resources) is somehow unaesthetic.
Thank you.

Answer 1

resources :categories, :path => '' do
  resources :posts, :path => ''
end

Answer 2

get '/:category/:post' => 'controller#action'
Replace with the necessary one only, and so all this is written in the documentation.