test sum

app/models/cash_balance.rb

@@ -41,10 +41,10 @@ class CashBalance < ActiveRecord::Base
       return self.count
     end
   end
-  const total=0
+  $total=0
   def get_happen_total
-    total= total+self.count
-    return total
+    $total= $total+self.count
+    return $total
   end
 
   def profit_state