Fix duplicate shallow routes

[visini]

With something like this...

Rails.application.routes.draw do
  resources :teams, only: [] do
    resources :comments, only: [:show, :update], shallow: true
  end
  resources :groups, only: [] do
    resources :comments, only: [:show, :update], shallow: true
  end
end

... I saw that it generates two updates in the controller.

Before:

comment: ...  // GET /comments/:id
update:  ...  // PATCH /comments/:id
show:    ...  // GET /comments/:id
update:  ...  // PATCH /comments/:id <- Duplicate

After:

show:   ...   // GET /comments/:id
update: ...   // PATCH /comments/:id