add iqdb preview

config/routes.rb

@@ -157,6 +157,7 @@ Rails.application.routes.draw do
   resources :ip_bans
   resource :iqdb_queries, :only => [:show]  do
     collection do
+      get :preview
       get :check, to: redirect {|path_params, req| "/iqdb_queries?#{req.query_string}"}
     end
   end