Add new 'Checkout options' step to the edit order cycle form so people can attach shipping methods

app/models/order_cycle.rb

@@ -156,6 +156,23 @@ class OrderCycle < ApplicationRecord
     ]
   end
 
+  def attachable_payment_methods
+    Spree::PaymentMethod.available(:both).
+      joins("INNER JOIN distributors_payment_methods
+             ON payment_method_id = spree_payment_methods.id").
+      where("distributor_id IN (?)", distributor_ids).
+      distinct
+  end
+
+  def attachable_shipping_methods
+    return Spree::ShippingMethod.none if simple? || !shipping_methods_customisable?
+
+    Spree::ShippingMethod.frontend.
+      joins(:distributor_shipping_methods).
+      where("distributor_id IN (?)", distributor_ids).
+      distinct
+  end
+
   def clone!
     oc = dup
     oc.name = I18n.t("models.order_cycle.cloned_order_cycle_name", order_cycle: oc.name)

app/models/spree/ability.rb

@@ -243,7 +243,9 @@ module Spree
     end
 
     def add_order_cycle_management_abilities(user)
-      can [:admin, :index, :read, :edit, :update, :incoming, :outgoing], OrderCycle do |order_cycle|
+      can [
+        :admin, :index, :read, :edit, :update, :incoming, :outgoing, :checkout_options
+      ], OrderCycle do |order_cycle|
         OrderCycle.visible_by(user).include? order_cycle
       end
       can [:admin, :index, :create], Schedule