add intro route shortcut, optimize Favorite.remove

app/models/favorite.rb

@@ -34,7 +34,7 @@ class Favorite < ActiveRecord::Base
       User.where(:id => user.id).select("id").lock("FOR UPDATE NOWAIT").first
 
       return unless Favorite.for_user(user.id).where(:user_id => user.id, :post_id => post.id).exists?
-      Favorite.for_user(user.id).where(post_id: post.id).delete_all
+      Favorite.destroy_all(user_id: user.id, post_id: post.id)
       updates = "fav_count = fav_count - 1"
       updates = "#{updates}, score = score - 1" if user.is_gold?
       Post.where(:id => post.id).update_all(updates)

config/routes.rb

@@ -411,5 +411,7 @@ Rails.application.routes.draw do
   get "/static/name_change" => "static#name_change", :as => "name_change"
   get "/meta_searches/tags" => "meta_searches#tags", :as => "meta_searches_tags"
 
+  get "/intro" => redirect("/explore/posts/intro")
+
   root :to => "posts#index"
 end