Single database for multiple shops

Use ActsAsTenant as Multi-tenancy for shops

See below files:
- app/controllers/concern/multi_tenancy.rb
- app/models/application_record.rb
- app/models/shop.rb

An initializer can be created to control option in ActsAsTenant.
config/initializers/acts_as_tenant.rb
require 'acts_as_tenant/sidekiq'
ActsAsTenant.configure do |config|
  config.require_tenant = false # true
end

more details: https://github.com/ErwinM/acts_as_tenant

app/controllers/settings/shops_controller.rb

@@ -59,11 +59,11 @@ class Settings::ShopsController < ApplicationController
                   File.delete(delete_path) 
                 end  
               end              
-              save_path = Rails.root.join("public/#{current_shop.shop_code}_#{a.original_filename}")
+              save_path = Rails.root.join("public/#{Shop.current_shop.shop_code}_#{a.original_filename}")
               File.open(save_path, 'wb') do |f|
                 f.write a.read
               end
-              audio_name = "#{current_shop.shop_code}_#{a.original_filename}"
+              audio_name = "#{Shop.current_shop.shop_code}_#{a.original_filename}"
               @settings_shop.display_images.where(:name => "order_audio").destroy_all
               @display_image = @settings_shop.display_images.create!(:shop_id => @shop.id, :name => "order_audio", :image => audio_name)
             else