added dotenv gem, upgrade to Rails 4.1.8
dotenv settings for Rails
capistrano dotenv setup
added .env.example configuration
vagrantfile for dotenv
rails dotenv configuration
use ENV variables in database.yml and settings.yml
added API key to example file
updated Cheffile
updated Cheffile
updated .travis.yml
deleted APP_CONFIG initializer
deleted settings files that are no longer needed
added ENV variables to environments
replace APP_CONFIG by ENV
settings.yml is no longer needed
secret_token is read from secrets.yml
temporarily disable exception notification webhook
added remaining configuration options to .env.example
check for required ENV variables