Keep old customers.name column for compatibilty

Our app code will try to access the old attribute while the migration is
running. That would lead to errors during checkout.

db/migrate/20220105085729_split_customers_name.rb

@@ -1,6 +1,9 @@
+# frozen_string_literal: true
+
 class SplitCustomersName < ActiveRecord::Migration[6.1]
   class SpreeAddress < ApplicationRecord
   end
+
   class Customer < ApplicationRecord
     belongs_to :bill_address, class_name: "SpreeAddress"
   end
@@ -8,7 +11,6 @@ class SplitCustomersName < ActiveRecord::Migration[6.1]
   def up
     add_column :customers, :first_name, :string, null: false, default: ""
     add_column :customers, :last_name, :string, null: false, default: ""
-    rename_column :customers, :name, :backup_name
 
     migrate_customer_name_data!
   end
@@ -16,12 +18,11 @@ class SplitCustomersName < ActiveRecord::Migration[6.1]
   def down
     remove_column :customers, :first_name
     remove_column :customers, :last_name
-    rename_column :customers, :backup_name, :name
   end
 
   def migrate_customer_name_data!
-    Customer.where(first_name: "", last_name: "").where.not(backup_name: [nil, ""]).find_each do |customer|
-      name_words = customer.backup_name.split(' ')
+    Customer.where(first_name: "", last_name: "").where.not(name: [nil, ""]).find_each do |customer|
+      name_words = customer.name.split(' ')
       next if name_words.empty?
 
       customer.update(

db/schema.rb

@@ -51,7 +51,7 @@ ActiveRecord::Schema.define(version: 2022_01_18_053107) do
     t.datetime "updated_at", null: false
     t.integer "bill_address_id"
     t.integer "ship_address_id"
-    t.string "backup_name", limit: 255
+    t.string "name", limit: 255
     t.boolean "allow_charges", default: false, null: false
     t.datetime "terms_and_conditions_accepted_at"
     t.string "first_name", default: "", null: false