FIX: faster update of all badges

Introduced badge triggers, introduced concept of badge that happens due to a post but has the post hidden

Delta badge grant happens once a minute, backed by redis

db/migrate/20140723011456_add_show_posts_to_badges.rb

@@ -0,0 +1,6 @@
+class AddShowPostsToBadges < ActiveRecord::Migration
+  def change
+    # show posts to users on badge show page
+    add_column :badges, :show_posts, :boolean, null: false, default: false
+  end
+end