Allow null for customers.created_manually

Some production database don't allow null for customers.created_maually,
we want to allow it to bring the database inline with schema.rb

db/migrate/20250113055412_customers_created_manually_remove_null.rb

@@ -0,0 +1,5 @@
+class CustomersCreatedManuallyRemoveNull < ActiveRecord::Migration[7.0]
+  def change
+    change_column_null :customers, :created_manually, true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2024_11_13_185651) do
+ActiveRecord::Schema[7.0].define(version: 2025_01_13_055412) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_stat_statements"
   enable_extension "plpgsql"