Add .env.docker.example as a template for Docker-based local
development, and add a negation pattern to .gitignore so the
example file is tracked while real .env* files stay ignored.
Signed-off-by: Fabian Mossberg <fabian@hejfaktura.se>
Co-authored-by: Jakob Wennberg <jakob.wennberg@gmail.com>
Fabian Mossberg