message: issue comment explaining controller test job in circleci config
diff: version: 2.1
  jobs:
  + # This job creates an image that has the necessary tools to build and test the controller code, then runs it.
  + # It replicates the same environment as the one used in TravisCI (see the .travis.yml file in this repo),
  + # though without the GUI build tools and dependencies.
  controller-test:
  # See https://circleci.com/docs/2.0/executor-types/#docker-benefits-and-limitations
  # We use a machine executor here because we must run the container in privileged mode.
  