Right now namespace and config_file and soon config_env are defined on the module itself, while its only a handful of methods, it might be cleaner to do this in a configuration block:

module ExampleConfig
  extend ConfigModule
  config_module do
    file 'config/example.yml'
    env :example
    namespace config_module.env
  end
end

or maybe...

module ExampleConfig
  extend ConfigModule.setup do
    file 'config/example.yml'
    env :example
    namespace config_module.env
  end
end

This would also allow for lazy evaluation of methods that will be defined by the user on the module itself.