extracted regex into initializer

app/models/location.rb

@@ -1,5 +1,4 @@
 class Location < ApplicationRecord
-  include Validations::PropertyValidations
   validate :validate_postcode
   belongs_to :scheme
 
@@ -36,7 +35,7 @@ class Location < ApplicationRecord
 private
 
   def validate_postcode
-    if postcode.nil? || !postcode&.match(Validations::PropertyValidations::POSTCODE_REGEXP)
+    if postcode.nil? || !postcode&.match(POSTCODE_REGEXP)
       error_message = I18n.t("validations.postcode")
       errors.add :postcode, error_message
     end

app/models/validations/property_validations.rb

@@ -1,7 +1,6 @@
 module Validations::PropertyValidations
   # Validations methods need to be called 'validate_<page_name>' to run on model save
   # or 'validate_' to run on submit as well
-  POSTCODE_REGEXP = /^(([A-Z]{1,2}[0-9][A-Z0-9]?|ASCN|STHL|TDCU|BBND|[BFS]IQQ|PCRN|TKCA) ?[0-9][A-Z]{2}|BFPO ?[0-9]{1,4}|(KY[0-9]|MSR|VG|AI)[ -]?[0-9]{4}|[A-Z]{2} ?[0-9]{2}|GE ?CX|GIR ?0A{2}|SAN ?TA1)$/i
 
   def validate_property_number_of_times_relet(record)
     return unless record.offered

config/initializers/postcode_regex.rb

@@ -0,0 +1 @@
+POSTCODE_REGEXP = /^(([A-Z]{1,2}[0-9][A-Z0-9]?|ASCN|STHL|TDCU|BBND|[BFS]IQQ|PCRN|TKCA) ?[0-9][A-Z]{2}|BFPO ?[0-9]{1,4}|(KY[0-9]|MSR|VG|AI)[ -]?[0-9]{4}|[A-Z]{2} ?[0-9]{2}|GE ?CX|GIR ?0A{2}|SAN ?TA1)$/i