BUGFIX: add default value to top_topics' scores

db/migrate/20140408152401_add_default_value_to_top_topic_scores.rb

@@ -0,0 +1,7 @@
+class AddDefaultValueToTopTopicScores < ActiveRecord::Migration
+  def change
+    TopTopic.periods.each do |period|
+      change_column_default :top_topics, "#{period}_score".to_sym, 0
+    end
+  end
+end