Rails redirect to default locale

routes.rb

Rails.application.routes.draw do

  scope "/:locale" do
    # blablabla..
  end
  
  root to: "welcome#index"
  get '/:locale' => 'welcome#index', :as => 'locale_root'

end

welcome_controller.rb

class WelcomeController < ApplicationController
  def index
    
    if(params[:locale].nil?)
      redirect_to locale_root_path, :status => :moved_permanently
    end

  end
end