Place all your configuration parameters in YAML files within a config/ directory under the top level of your project. For example, you might have a config/database.yml file.

In an initializer at the top level of your project, or within your config/ directory, do this:

require 'constantinople'

You may then use CONSTANTINOPLE from anywhere in your app:

CONSTANTINOPLE.database.username

You can create default and over-ride versions of config files. Constantinople will look for and load config files in the following order:

config/*.yml.default
config/*.yml
config/*.yml.override

The results are merged together. We recommended you gitignore config/*.yml.

If there is a non-empty ENV['RAILS_ENV'], ENV['RACK_ENV'] or ENV['APP_ENV'] the first such environment will be used as a key whose values will be merged into the level above. If none of those are defined, 'development' is used. So for example, if your database.yml file has

username: root
password:
production:
  password: d87gfds09ds8a

Then in your development environment:

CONSTANTINOPLE.database.username # root
CONSTANTINOPLE.database.password # nil

And in your production environment:

CONSTANTINOPLE.database.username # root
CONSTANTINOPLE.database.password # d87gfds09ds8a

Install rvm, including ruby 1.9.2 Clone the git repo, then...

cd constantinople
gem install bundler
bundle install
rake coverage

Yeah, fine. But please rename to Istanbul.