Fix invalid routes for /posts, /explore/posts.

Fixes these invalid routes:

* GET http://danbooru.donmai.us/posts/new
* GET http://danbooru.donmai.us/posts/1234/edit
* POST http://danbooru.donmai.us/posts
* DELETE http://danbooru.donmai.us/posts
* GET http://danbooru.donmai.us/explore/posts

config/routes.rb

@@ -45,7 +45,7 @@ Rails.application.routes.draw do
     end
   end
   namespace :explore do
-    resources :posts do
+    resources :posts, :only => [] do
       collection do
         get :popular
         get :viewed
@@ -196,7 +196,7 @@ Rails.application.routes.draw do
     end
   end
   resources :post_replacements, :only => [:index, :new, :create, :update]
-  resources :posts do
+    resources :posts, :only => [:index, :show, :update] do
     resources :events, :only => [:index], :controller => "post_events"
     resources :replacements, :only => [:index, :new, :create], :controller => "post_replacements"
     resource :artist_commentary, :only => [:index, :show] do