Simple custom configuration within Rails App using initializer and YAML file.

application_controller.rb

# or in any other file

MY_CONFIG[:foo]

my_config.rb

# config/initializers/my_config.rb

config_file = File.expand_path('../../my_config.yml', __FILE__)

MY_CONFIG = File.exists?(config_file) ? YAML.load(File.read(config_file)) : {}
MY_CONFIG.symbolize_keys!

my_config.yml

# config/my_config.rb

---
  :foo: boo

Simple YAML configuration

Based on http://railscasts.com/episodes/85-yaml-configuration-revised