DB credentials checked into codebase

[harlantwood]

Recommend fix: use the awesome dotenv package to load environment variables either from process.env (if they exist there, as on Heroku) or from a local .env file, typically on a dev box.

I will create a PR once #642 is merged (otherwise the diff will not make sense) -- I created a PR in my own repo to show a demo of how this would work: https://github.com/harlantwood/cograph/pull/1/files

[harlantwood]

Also we would want notes in the README:

To get started in your local dev env: cp .env.example .env Change any credentials to your own databases, etc

[willzeng]

Yep we should go in this direction as soon as we sort the CI in #642. +1