gistfile1.rb

require 'yaml'

# Retains as a constant
CONFIG = YAML.load_file('config.yml')

# or
# Retains as an instance variable.

class Config
  def initialize(name)
    @name = name
  end
  
  def get
    @config ||= get_from_disk()
  end
private
  def get_from_disk
    YAML.load_file(@name)
  end
end

config = Config.new('config.yml')
p config.get