You may wish to organize groups of controllers under a namespace. Most commonly, you might group a number of administrative controllers under an admin namespace. You would place these controllers under the app/controllers/admin directory, and you can group them together in your router:

namespace "admin" do
  resources :posts, :comments
end

This will create a number of routes for each of the posts and comments controller. For Admin::PostsController, Rails will create:

GET       /admin/posts
GET       /admin/posts/new
POST      /admin/posts
GET       /admin/posts/1
GET       /admin/posts/1/edit
PATCH/PUT /admin/posts/1
DELETE    /admin/posts/1

If you want to route /posts (without the prefix /admin) to Admin::PostsController, you could use

scope module: "admin" do
  resources :posts
end

or, for a single case

resources :posts, module: "admin"

If you want to route /admin/posts to PostsController

(without the Admin

module prefix), you could use

scope "/admin" do
  resources :posts
end

or, for a single case

resources :posts, path: "/admin/posts"

In each of these cases, the named routes remain the same as if you did not use scope. In the last case, the following paths map to PostsController:

GET       /admin/posts
GET       /admin/posts/new
POST      /admin/posts
GET       /admin/posts/1
GET       /admin/posts/1/edit
PATCH/PUT /admin/posts/1
DELETE    /admin/posts/1