Fix ActiveJob::Performs not being automatically extended

`ActiveSupport.on_load :active_job` may not fire after the application has loaded (since it happens when Active Job is first mentioned and then it's loaded),
which means any Associated Objects loaded would not have `performs` defined and we'd raise.

The short curcuit was to only inject performs if users were using Active Job, but it's too clever.

We're now being less clever and letting bundler load every gem first via deferring our extension to the others in `config.after_initialize`.

lib/active_record/associated_object/railtie.rb

@@ -3,17 +3,12 @@ class ActiveRecord::AssociatedObject::Railtie < Rails::Railtie
     config.after_initialize do
       ActiveRecord::AssociatedObject.include Kredis::Attributes       if defined?(Kredis)
       ActiveRecord::AssociatedObject.include GlobalID::Identification if defined?(GlobalID)
+
+      ActiveRecord::AssociatedObject.extend ActiveJob::Performs if defined?(ActiveJob::Performs)
     end
   end
 
   initializer "object_association.setup" do
-    ActiveSupport.on_load :active_job do
-      require "active_job/performs"
-      ActiveRecord::AssociatedObject.extend ActiveJob::Performs
-    rescue LoadError
-      # We haven't bundled active_job-performs, so we're continuing without it.
-    end
-
     ActiveSupport.on_load :active_record do
       require "active_record/associated_object/object_association"
       include ActiveRecord::AssociatedObject::ObjectAssociation

test/test_helper.rb

@@ -4,14 +4,16 @@
 
 require "rails/railtie"
 require "kredis"
-require "active_job"
-require "global_id"
 require "debug"
 require "logger"
 
 require "active_record"
 require "active_record/associated_object"
 
+require "global_id"
+require "active_job"
+require "active_job/performs"
+
 require "minitest/autorun"
 
 # Simulate Rails app boot and run the railtie initializers manually.