model add scope

app/models/product.rb

@@ -117,7 +117,6 @@ class Product < ActiveRecord::Base
     end
 
     def gross_interest_rate
-        controller = bindings[:controller]
         rate = 0
         if self.buy_price != 0 && self.price != 0
             rate = (( self.price.to_f - self.buy_price.to_f )/self.buy_price.to_f)*100