diff --git a/Dockerfile b/Dockerfile
index 99b08d0e..5990b89e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -29,6 +29,7 @@ VOLUME /pcw/db
 
 EXPOSE 8000/tcp
 
+# Required to use system certs in python-requests
 ENV REQUESTS_CA_BUNDLE=/etc/ssl/ca-bundle.pem
 
 # Once we are certain that this runs nicely, replace this with ENTRYPOINT.