environment variables not respected

[predmond]

I have a docker-compose file using this docker file and

  protractor:
    ...
    environment:
      - PGHOST=db

When I run the protractor container the PGHOST variable is not set. I believe this is because of the use of sudo in
sudo -u protractor xvfb-run --server-args="-screen 0 ${SCREEN_RES}" -a protractor $@

This should probably be sudo -E -u protractor ... to preserve the environment.