don't use sqlite3 for production
heroku specific config
adds rails_12factor for Heroku

See https://devcenter.heroku.com/articles/ruby-support#injected-plugins
Use unicorn for Heroku

See https://devcenter.heroku.com/articles/rails-unicorn
fixes policy configuration issue
fixes seed file test
apply strict policy
force authentication
makes rspec working

TODO: some Capybara test (feature) do not pass due to translation issues
enforces policies and fixes application policy