implement before validation check to ensure that if the user declares no mortgage will be used, mortgage value is set to 0

app/models/sales_log.rb

@@ -29,6 +29,7 @@ class SalesLog < Log
   before_validation :process_previous_postcode_changes!, if: :ppostcode_full_changed?
   before_validation :reset_location_fields!, unless: :postcode_known?
   before_validation :reset_previous_location_fields!, unless: :previous_postcode_known?
+  before_validation :set_mortgage_value_zero, if: :mortgage_not_used?
 
   scope :filter_by_year, ->(year) { where(saledate: Time.zone.local(year.to_i, 4, 1)...Time.zone.local(year.to_i + 1, 4, 1)) }
   scope :search_by, ->(param) { filter_by_id(param) }
@@ -186,6 +187,10 @@ class SalesLog < Log
     mortgageused == 2
   end
 
+  def set_mortgage_value_zero
+    self.mortgage = 0
+  end
+
   def process_postcode_changes!
     self.postcode_full = upcase_and_remove_whitespace(postcode_full)
     process_postcode(postcode_full, "pcodenk", "is_la_inferred", "la")