there's no such thing as Array#to_h

(cherry picked from commit 780bd84bc17f55b0ece1d86a2b224f0340495c73)
Merge pull request #499 from openSUSE/arrays_and_hashes_oh_my

there's no such thing as Array#to_h
Invite Postgres to the party.
Include suggested ruby version in Gemfile
Use environment variables for production secrets...

... so no need for copying the example file.
Use a single email address for sending mails.
Use environment variables for production config...

... so no need for example config.
Enable external SMTP server if necessary, via environment vars.
logo, 1st draft
Enable Unicorn as a production web server.

Conflicts:
	Gemfile
Ignore .env
Use environment variable for production database...

... so no need for copying the example file.
Add heroku app definition
Add 'Deploy to Heroku' button and instructions.