Add fix for counter_cache migration to keep from throwing readonly column error.

data/sql/migrate/20120601152442_add_counter_caches_to_hosts.rb

@@ -1,14 +1,15 @@
 class AddCounterCachesToHosts < ActiveRecord::Migration
+
   def self.up
     add_column :hosts, :note_count, :integer, :default => 0
     add_column :hosts, :vuln_count, :integer, :default => 0
     add_column :hosts, :service_count, :integer, :default => 0
-    
+  
     Mdm::Host.reset_column_information
     Mdm::Host.all.each do |h|
-      h.update_attribute :note_count, h.notes.length
-      h.update_attribute :vuln_count, h.vulns.length
-      h.update_attribute :service_count, h.services.length
+      Mdm::Host.reset_counters h.id, :notes
+      Mdm::Host.reset_counters h.id, :vulns
+      Mdm::Host.reset_counters h.id, :services
     end
   end
 
@@ -17,4 +18,4 @@ class AddCounterCachesToHosts < ActiveRecord::Migration
     remove_column :hosts, :vuln_count
     remove_column :hosts, :service_count
   end
-end
+end