== Welcome to a simple multi-association scope merge join test This app demos a limitation on merging a scope that includes a join across a second association. ``` rake db:migrate rails c Parent.test_scope.to_sql ``` Raises an exception: ActiveRecord::ConfigurationError: Association named 'grandchildren' was not found; perhaps you misspelled it? I think this means that AR (or Squeel, I'm not sure), is trying to find the 'grandchildren' association on the Parent model.