FEATURE: top topics all time

tweak top algorithm (we will continue next week)

db/migrate/20150306050437_add_all_time_and_op_likes_to_top_topics.rb

@@ -0,0 +1,10 @@
+class AddAllTimeAndOpLikesToTopTopics < ActiveRecord::Migration
+  def change
+    add_column :top_topics, :all_score, :float, default: 0
+    [:daily, :weekly, :monthly, :yearly].each do |period|
+      column = "#{period}_op_likes_count"
+      add_column :top_topics, column, :integer, default: 0, null: false
+      add_index :top_topics, [column]
+    end
+  end
+end