add shopify rubocop

config/environments/development.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "active_support/core_ext/integer/time"
 
 Rails.application.configure do
@@ -16,13 +17,13 @@ Rails.application.configure do
 
   # Enable/disable caching. By default caching is disabled.
   # Run rails dev:cache to toggle caching.
-  if Rails.root.join('tmp', 'caching-dev.txt').exist?
+  if Rails.root.join("tmp/caching-dev.txt").exist?
     config.action_controller.perform_caching = true
     config.action_controller.enable_fragment_cache_logging = true
 
     config.cache_store = :memory_store
     config.public_file_server.headers = {
-      'Cache-Control' => "public, max-age=#{2.days.to_i}"
+      "Cache-Control" => "public, max-age=#{2.days.to_i}",
     }
   else
     config.action_controller.perform_caching = false