Update external database docs to mention migrator (!31948) · Merge requests · Administrator / sourcegraph · GitLab

Administrator requested to merge caug/update-external-database-docs into main Feb 28, 2022

Created by: caugustus-sourcegraph

Improve external database docs to mention the migrator container.

Related: https://github.com/sourcegraph/customer/issues/733

Test plan

N/A, doc update only