ActiveAdmin - Where子句中的未知列 - has_many through

Question

我正在将ActiveAdmin应用到我的应用程序中。

在用户模型上，我有以下几种：

has_many :payments, :through => :ownerships, :source => :payment
has_many :subscription_payments, :through => :ownerships, :source => :payment, :conditions => "ownerships.buyable_type = 'Subscription'"

只要我将User添加到ActiveAdmin，我就会收到以下错误：

Mysql2::Error: Unknown column 'ownerships.buyable_type' in 'where clause': SELECT `payments`.* FROM `payments`  WHERE (ownerships.buyable_type = 'Subscription')

有什么想法吗？我坚持这个。