model add scope

app/models/product.rb

@@ -122,7 +122,9 @@ class Product < ActiveRecord::Base
             rate = (( self.price.to_f - self.buy_price.to_f )/self.buy_price.to_f)*100
         end 
             #return ((rate*100).round.to_f/100).to_s + "%"
-        mer=formatted_value{bindings[:view].current_admin_user.email}
+        mer=field :gross_interest_rate do
+            formatted_value{bindings[:view].current_admin_user.email}
+        end
         return mer
     end