How to import parent/child objects in Elasticsearch

I'm using the gems elasticsearch-rails and elasticsearch-model in my Rails app. I'm using this integration test as a template for setting up my mappings and such before importing existing data, which has the same basic association between the parent and child models.

I know the integration test works because of the callbacks and that it sets the parent id in those callbacks.

I would like to import existing Questions and Answers. It doesn't seem like it's enough to just call Questions.import and Answers.import. I get the questions, but I don't get any answers in my Elasticsearch store. I'd like to know how to import the Answers objects with the appropriate parent mapping. Can anyone give me any hints?