White listing all Impression attributes according to new Rails active_record.whitelist default.

app/models/impression.rb

@@ -3,6 +3,10 @@ class Impression < ActiveRecord::Base
 
   after_save :update_impressions_counter_cache
 
+  attr_accessible :impressionable_type, :impressionable_id, :user_id,
+  :controller_name, :action_name, :view_name, :request_hash, :ip_address,
+  :session_hash, :message, :referrer
+
   private
 
   def update_impressions_counter_cache