dockerize

[EFulmer]

small changes to existing files:

• requirements.txt: different version for jinja2-cli (0.7.0-dev0 not on PyPI)
• Makefile: change test target to use specific host, port, and user (probably need to change run-db.sh and more commands too...)
• also, Dockerfile created (depends on my fork of https://github.com/efulmer/dockerfiles/, which will go on Docker Hub soon)