base_controller.rb

class Admin::BaseController < ApplicationController
end

dashboards_controller.rb

class Admin::DashboardsController < Admin::BaseContoller
end

directories

+controllers
  + admin
    + base_controller.rb
    + dashboards_contrller.rb

gistfile1.txt

uninitialized constant Admin::BaseContoller

routes.rb

Test::Application.routes.draw do
  
  namespace :admin do
    resources :dashboards
  end
  
end