nginx: set permissions on subdomain_forwarding
chef: set permissions on nginx proxy files
chef: extract create_keep_file
chef: add nginx_ssl_config_for_multiple_apps

Add attribute: main_app_name
Created: ConfigHelpers
Extracted: current_role default_app, main_app_name, secondary_apps
nginx_ssl: extract permission_mode, clean up.
chef: add food critic to rake :default

Needed rake in Gemfile
chef: add robots for robots.txt