Remove RAILS_ROOT from webrick_server docs.

Signed-off-by: Nwycats <wycats@gmail.com>

railties/lib/rails/webrick_server.rb

@@ -63,8 +63,8 @@ def self.dispatch(options = {})
   def initialize(server, options) #:nodoc:
     @server_options = options
     @file_handler = WEBrick::HTTPServlet::FileHandler.new(server, options[:server_root])
-    # Change to the RAILS_ROOT, since Webrick::Daemon.start does a Dir::cwd("/")
-    # OPTIONS['working_directory'] is an absolute path of the RAILS_ROOT, set in railties/lib/commands/servers/webrick.rb
+    # Change to the Rails.root, since Webrick::Daemon.start does a Dir::cwd("/")
+    # OPTIONS['working_directory'] is an absolute path of the Rails.root, set in railties/lib/commands/servers/webrick.rb
     Dir.chdir(OPTIONS['working_directory']) if defined?(OPTIONS) && File.directory?(OPTIONS['working_directory'])
     super
   end