Wrong Relationship

gistfile1.rb

> ActiveRecord::Base.logger = Logger.new(STDOUT)
> Infrastructure::Radio.first
Infrastructure::Radio Load (0.8ms)  SELECT "radio_channels".* FROM "radio_channels" LIMIT 1
+----+------------+
| id | ut_id_name |
+----+------------+
| 1  | 245        |
+----+------------+

> counter = 0; Infrastructure::Radio.first.foo.each {counter += 1}; puts counter
Infrastructure::Radio Load (0.4ms)  SELECT "radio_channels".* FROM "radio_channels" LIMIT 1
UserTranslation Load (1.0ms)  SELECT "user_translations".* FROM "user_translations"
 => 76

> Infrastructure::Radio.first.foo.count
Infrastructure::Radio Load (0.4ms)  SELECT "radio_channels".* FROM "radio_channels" LIMIT 1
UserTranslation Load (0.8ms)  SELECT "user_translations".* FROM "user_translations"
SQL (0.6ms)  SELECT COUNT(*) FROM "user_translations" WHERE ("user_translations".key = 245)
 => 1

radio.rb

# app/models/infrastructure/radio.rb

module Infrastructure
  class Radio < ActiveRecord::Base
    set_table_name 'radio_channels'

    has_many :foo, primary_key: :ut_id_name, foreign_key: :key, class_name: "UserTranslation"
  end
end