Routing Error when putting in routing scope for locale

Question

I am trying to implement internationalization using Rails I18n api. After going through the docs, it suggests doing routing scope in routes.rb file to persist between links in the page which I did something like this.

scope '(:locale)', locale: /en|es}/, defaults: {locale: "en"} do
  match 'pricing' => 'dashboard#show_pricing', :via => [:get]
end

Now when I run it on the localhost, using the url "localhost:3000/en/pricing", it is throwing a routing error

Rails -- Exception: ActionController::RoutingError: No route matches [GET] "/en/assets/spinner-loader.gif"

I have gone through other similar questions here but nothing seems to match.