Use relative -r path in production.txt
# PRECAUTION: avoid production dependencies that aren't in development
--r base.txt
+-r ./base.txt
gunicorn==19.8.1 # https://github.com/benoitc/gunicorn
psycopg2==2.7.4 --no-binary psycopg2 # https://github.com/psycopg/psycopg2
