```ruby
module KhipuRails

  extend self

  def configure
    @config = Config.default
    yield @config
  end

  attr_accessor :config
end```

Refactor of the configuration to have default configuration without call to cofigure
user
```ruby
module KhipuRails
  extend self

  def configure
    yield config
  end

  def config
    @config ||= Config.default
  end

  attr_writer :config
end```
assistant