如何扩展Spree::Adjustable::Adjuster?

How to extend Spree::Adjustable::Adjuster?

我正在尝试按照指南 (http://guides.spreecommerce.org/developer/adjustments.html) 中的说明扩展 Spree::Adjustable::Adjuster。指示并不难遵循,我按照它们到达了 T,但出现以下错误:

`<module:Adjuster>': uninitialized constant Spree::Adjustable::Adjuster::Base (NameError)

您使用的是哪个版本的 Spree?

此功能是在 3.1 中添加的。

https://github.com/spree/spree/blame/3-1-stable/core/app/models/spree/adjustable/adjuster/base.rb

https://github.com/spree/spree/blame/master/guides/content/developer/core/adjustments.md#L99-L146