add top page

db/migrate/20131223171005_create_top_topics.rb

@@ -0,0 +1,23 @@
+class CreateTopTopics < ActiveRecord::Migration
+  def change
+    create_table :top_topics do |t|
+      t.belongs_to :topic
+
+      TopTopic.periods.each do |period|
+        TopTopic.sort_orders.each do |sort|
+          t.integer "#{period}_#{sort}_count".to_sym, null: false, default: 0
+        end
+      end
+
+    end
+
+    add_index :top_topics, :topic_id, unique: true
+
+    TopTopic.periods.each do |period|
+      TopTopic.sort_orders.each do |sort|
+        add_index :top_topics, "#{period}_#{sort}_count".to_sym, order: 'desc'
+      end
+    end
+
+  end
+end