Handle NullObject instances in Active Job query tag

Author: byroot

activejob/lib/active_job/railtie.rb

@@ -70,7 +70,7 @@ class Railtie < Rails::Railtie # :nodoc:
         end
 
         ActiveSupport.on_load(:active_record) do
-          ActiveRecord::QueryLogs.taggings[:job] = ->(context) { context[:job].class.name }
+          ActiveRecord::QueryLogs.taggings[:job] = ->(context) { context[:job].class.name unless context[:job].nil? }
         end
       end
     end