set associations on aux records

spec/active_record/has_aux_table_spec.rb

@@ -99,6 +99,18 @@ RSpec.describe HasAuxTable do
     expect(lot.vehicles.first.name).to eq("vehicle1")
   end
 
+  it "can set association on aux record" do
+    driver = Driver.create!(name: "John Doe")
+    car = Car.create!(name: "Honda Civic")
+    driver.car = car
+    expect(driver.car).to eq(car)
+    expect(driver.car_id).to eq(car.id)
+    driver.save!
+
+    driver = Driver.find(driver.id)
+    expect(driver.car).to eq(car)
+  end
+
   describe "#changed?" do
     it "returns true if the main record changes" do
       car = Car.create!(name: "Honda Civic")

spec/spec_helper.rb

@@ -90,7 +90,6 @@ module SpecHelper
         t.create_aux :driver do |t|
           t.integer :license_number
           t.references :car,
-                       null: false,
                        foreign_key: {
                          to_table: :vehicles_car_aux,
                          primary_key: :base_table_id

spec/spec_models.rb

@@ -28,7 +28,7 @@ end
 
 class Driver < Person
   aux_table :driver
-  belongs_to :car, inverse_of: :drivers
+  belongs_to :car, optional: true
 end
 
 class Captain < Person