自连接的正确 ActiveRecord 关联 类

Question

我一直在修改在线 Rails 教程以满足我的特定需求，但我发现自己力不从心。一点点清晰度将不胜感激。我的代码在我的问题下面。

此时，如果dan和rob是classUser的实例，我调用

dan.add_supervisor(rob)

然后 returns 一个空集合：

dan.supervisors
=> #<ActiveRecord::Associations::CollectionProxy []>

然而监管本身已经创建：

dan.initiated_supervisions
=> #<ActiveRecord::Associations::CollectionProxy [#<Supervision id: 50, supervisor_id: 68, supervisee_id: 67, created_at: "2015-03-10 18:30:01", updated_at: "2015-03-10 18:30:01">]>

理想的行为是让 has_many :through 行为正常工作，并且能够通过调用 dan.supervisors 获得 Dan 的主管列表。我需要做出哪些改变才能实现这一目标？

User.rb

...

# Supervisees can choose their supervisors, 
# but not the other way around.

has_many :initiated_supervisions,     class_name: "Supervision", 
                                      foreign_key: "supervisee_id", 
                                      dependent: :destroy
has_many :non_initiated_supervisions, class_name: "Supervision", 
                                      foreign_key: "supervisor_id", 
                                      dependent: :destroy

has_many :supervisees, through: :non_initiated_supervisions
has_many :supervisors, through: :initiated_supervisions

...

def add_supervisor(other_user)
  initiated_supervisions.create(supervisor_id: other_user.id)
end

...

Supervision.rb

...

belongs_to :supervisor,    class_name: "User"
belongs_to :supervisee,    class_name: "User"
validates  :supervisor_id, presence:   true
validates  :supervisee_id, presence:   true

...

Answer 1

解决方案（暂时...拜托，哦，请继续工作...）在两个 User 模型关联中指定 class_name: "User"：

has_many :supervisors, through: :initiated_supervisions, class_name: "User"
has_many :supervisees, through: :non_initiated_supervisions, class_name: "User"