Load configs from ERB based YML files in Rails application

app_config.rb

module AppConfig
  def self._config
    @_config ||= ErbYaml.load_file("#{Rails.root}/config/app_configuration.yml")
  end
  
  def self.env
    _config["env_name"]
  end
end

app_configuration.yml

defaults: &defaults
  env_name: "<%= Rails.env %>"

development: &development
  <<: *defaults
qa:
  <<: *defaults

erb_yaml.rb

module ErbYaml
  def self.load_file(path, a_binding = binding)
    content = File.read(path)
    YAML.load(ERB.new(content).result(a_binding))[Rails.env]
  end
end