Context

Langchain supports[ running a MongoDB instance inside of docker|https://github.com/langchain-ai/langchain/blob/master/docker/docker-compose.yml#L27] during their test step. This could be better to use than our live atlas cluster. It would require scaffolding the docker. 

Definition of done

Update the mongo docker to have the langchain_test_db collections and index definitions.

Pitfalls

This should not affect our current AI/ML testing pipeline workflow.