also delegate register

lib/sinatra/base.rb

@@ -1759,7 +1759,7 @@ module Sinatra
     delegate :get, :patch, :put, :post, :delete, :head, :options, :template, :layout,
              :before, :after, :error, :not_found, :configure, :set, :mime_type,
              :enable, :disable, :use, :development?, :test?, :production?,
-             :helpers, :settings
+             :helpers, :settings, :register
 
     class << self
       attr_accessor :target