Since the application does not use a database, it's confusing to have to
set a bogus database URL environment variable. This change follows [the
Lucky guide][1] suggestion for disabling the need for database
configuration. That makes the setup a little easier.
[1]:
https://www.luckyframework.org/guides/database/intro-to-avram-and-orms
The most common is "How do I set my custom domain" (answer: APP_DOMAIN)
but this also requires setting LUCKY_ENV=production which requires
SECRET_KEY_BASE, DATABASE_URL, and PORT
This patch adds support for development with the Nix package manager. In
order to support the traditional nix-shell tool as well as the (still
experimental) Nix Flakes feature of the upcoming version of Nix, this
patch adds shell.nix *and* flake.nix/flake.lock. Usage instructions
have been added to the README.
