robots.txt: add more static pages.

Let Google index a few more static pages.

app/views/robots/index.text.erb

@@ -63,8 +63,13 @@ Allow: /images
 Allow: /packs
 
 <%# Static %>
-Allow: /terms_of_service
-Allow: /privacy
+Allow: <%= site_map_path %>
+Allow: <%= contact_path %>
+Allow: <%= keyboard_shortcuts_path %>
+Allow: <%= bookmarklet_path %>
+Allow: <%= terms_of_service_path %>
+Allow: <%= privacy_policy_path %>
+Allow: <%= not_found_path %>
 Allow: /sitemap.xml
 Allow: /favicon.ico
 

config/routes.rb

@@ -329,6 +329,7 @@ Rails.application.routes.draw do
   get "/opensearch" => "static#opensearch", :as => "opensearch"
   get "/privacy" => "static#privacy_policy", :as => "privacy_policy"
   get "/terms_of_service" => "static#terms_of_service", :as => "terms_of_service"
+  get "/404" => "static#not_found", :as => "not_found"
   get "/static/keyboard_shortcuts" => "static#keyboard_shortcuts", :as => "keyboard_shortcuts"
   get "/static/bookmarklet" => "static#bookmarklet", :as => "bookmarklet"
   get "/static/site_map" => "static#site_map", :as => "site_map"