add validation for payment method,print_setting,tax_profile

app/models/payment_method_setting.rb

@@ -1,2 +1,4 @@
 class PaymentMethodSetting < ApplicationRecord
+	# validations
+ 	validates_presence_of :payment_method, :gateway_communication_type, :gateway_url, :auth_token, :merchant_account_id
 end

app/models/print_setting.rb

@@ -1,2 +1,4 @@
 class PrintSetting < ApplicationRecord
+	# validations
+	validates_presence_of :name, :unique_code, :font, :api_settings, :printer_name, :page_width, :page_height, :print_copies, :heading_space
 end

app/models/tax_profile.rb

@@ -1,4 +1,5 @@
 class TaxProfile < ApplicationRecord
   default_scope { order('order_by asc') }
-
+  # validations
+  validates_presence_of :name, :rate
 end