Sphinx doc with Basic Authentication with Heroku on Docker container

How to use?

1. put your documentation in /doc.

2. testing:

   docker build -t webapp .
   docker run --rm -e BASIC_AUTH=heroku:docker -e PORT=8080-p 8080:8080 webapp
   curl http://localhost:8080/

3. deploy onto heroku:

   heroku login
   heroku container:login
   heroku create
   heroku container:push web
   heroku container:release web
   heroku open

refs: https://devcenter.heroku.com/articles/container-registry-and-runtime