Was surprising found that this example doesn't work:

  scope :api do
    resources :users
  end

and the right form to use it is:

  scope 'api' do
    resources :users
  end

I think this should work similary as `namespace` where both are allowed.
These two are equivalent:

  namespace :api do
    resources :users
  end

  namespace 'api' do
    resources :user
  end