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

app/views/print_settings/edit.html.erb

@@ -4,7 +4,7 @@
     <li class="breadcrumb-item"><a href="<%= print_settings_path %>">Print Setting</a></li>
     <li class="breadcrumb-item active">Edit</li>
     <span class="float-right">
-      <%= link_to t('.new', :default => t("views.btn.new")), print_settings_path %>
+      <%= link_to t('.back', :default => t("views.btn.back")), print_settings_path %>
     </span>
   </ol>
 </div>