Move some common elements of TransactionAssignments to a single module

app/models/campaign_gift_purchase.rb

@@ -3,23 +3,14 @@
 # License: AGPL-3.0-or-later WITH WTO-AP-3.0-or-later
 # Full license explanation at https://github.com/houdiniproject/houdini/blob/master/LICENSE
 class CampaignGiftPurchase < ApplicationRecord
-  include Model::Houidable
-  include Model::Jbuilder
-  include Model::Eventable
+  include Model::TrxAssignable
 
   setup_houid :cgpur
 
   belongs_to :campaign
   has_many :campaign_gifts, class_name: 'ModernCampaignGift'
 
-  add_builder_expansion :nonprofit, :supporter, :campaign
-  add_builder_expansion :trx, 
-		json_attrib: :transaction
-		
-	has_one :transaction_assignment, as: :assignable
-	has_one :trx, through: :transaction_assignment
-	has_one :supporter, through: :trx
-	has_one :nonprofit, through: :supporter
+  add_builder_expansion :campaign
 
 
   # TODO replace with Discard gem

app/models/concerns/model/trx_assignable.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# License: AGPL-3.0-or-later WITH WTO-AP-3.0-or-later
+# Full license explanation at https://github.com/houdiniproject/houdini/blob/master/LICENSE
+module Model::TrxAssignable
+	extend ActiveSupport::Concern
+
+	included do
+		include Model::Houidable
+		include Model::Jbuilder
+		include Model::Eventable
+
+		add_builder_expansion :nonprofit, :supporter
+
+		add_builder_expansion :trx, 
+			json_attrib: :transaction
+
+		has_one :transaction_assignment, as: :assignable
+		has_one :trx, through: :transaction_assignment
+		has_one :supporter, through: :trx
+		has_one :nonprofit, through: :supporter
+	end
+end

app/models/modern_donation.rb

@@ -3,20 +3,10 @@
 # License: AGPL-3.0-or-later WITH WTO-AP-3.0-or-later
 # Full license explanation at https://github.com/houdiniproject/houdini/blob/master/LICENSE
 class ModernDonation < ApplicationRecord
-	include Model::Houidable
-  include Model::Jbuilder
-  include Model::Eventable
+  include Model::TrxAssignable
   setup_houid :don
 
 	# TODO must associate with events and campaigns somehow
-  add_builder_expansion :nonprofit, :supporter
-  add_builder_expansion :trx, 
-		json_attrib: :transaction
-		
-	has_one :transaction_assignment, as: :assignable
-	has_one :trx, through: :transaction_assignment
-	has_one :supporter, through: :trx
-	has_one :nonprofit, through: :supporter
 	belongs_to :legacy_donation, class_name: 'Donation', foreign_key: :donation_id, inverse_of: :modern_donation
 
 	delegate :designation, :dedication, to: :legacy_donation

app/models/ticket_purchase.rb

@@ -3,14 +3,10 @@
 # License: AGPL-3.0-or-later WITH WTO-AP-3.0-or-later
 # Full license explanation at https://github.com/houdiniproject/houdini/blob/master/LICENSE
 class TicketPurchase < ApplicationRecord
-  include Model::Houidable
-  include Model::Jbuilder
-  include Model::Eventable
+  include Model::TrxAssignable
   setup_houid :tktpur
 
-  add_builder_expansion :event, :nonprofit, :supporter
-  add_builder_expansion :trx, 
-    json_attrib: :transaction
+  add_builder_expansion :event
   
   add_builder_expansion :event_discount,
     to_id: -> (model) { model.event_discount&.id },
@@ -20,10 +16,6 @@ class TicketPurchase < ApplicationRecord
 
   belongs_to :event_discount
   belongs_to :event
-  has_one :transaction_assignment, as: :assignable
-  has_one :trx, through: :transaction_assignment
-  has_one :supporter, through: :trx
-  has_one :nonprofit, through: :supporter
   
   has_many :ticket_to_legacy_tickets