Use active record cache when available

lib/sidekiq/middleware/server/active_record_cache.rb

@@ -0,0 +1,11 @@
+module Sidekiq
+  module Middleware
+    module Server
+      class ActiveRecordCache
+        def call(*args, &block)
+          ::ActiveRecord::Base.cache(&block)
+        end
+      end
+    end
+  end
+end

lib/sidekiq/rails.rb

@@ -9,10 +9,15 @@ class Rails < ::Rails::Engine
     # class block. Definitely before config/environments/*.rb and
     # config/initializers/*.rb.
     config.before_configuration do
-      if ::Rails::VERSION::MAJOR < 5 && defined?(::ActiveRecord)
+      if defined?(::ActiveRecord)
         Sidekiq.server_middleware do |chain|
-          require 'sidekiq/middleware/server/active_record'
-          chain.add Sidekiq::Middleware::Server::ActiveRecord
+          if ::Rails::VERSION::MAJOR < 5
+            require 'sidekiq/middleware/server/active_record'
+            chain.add Sidekiq::Middleware::Server::ActiveRecord
+          end
+
+          require 'sidekiq/middleware/server/active_record_cache'
+          chain.add Sidekiq::Middleware::Server::ActiveRecordCache
         end
       end
     end
@@ -54,4 +59,4 @@ def inspect
   $stderr.puts("**************************************************")
   $stderr.puts("⛔️ WARNING: Sidekiq server is no longer supported by Rails 3.2 - please ensure your server/workers are updated")
   $stderr.puts("**************************************************")
-end
+end