--- migrate_from_trac.rake.orig 2008-04-07 06:23:03.000000000 +0000
+++ migrate_from_trac.rake      2008-04-07 06:24:45.000000000 +0000
@@ -19,6 +19,17 @@
 require 'iconv'
 require 'pp'

+class String
+  alias original_indexer []
+  def [](pos, length = 0)
+    if length == 0
+      self.original_indexer(pos)
+    else
+      self.split(//)[pos, length].join
+    end
+  end
+end
+
 namespace :redmine do
   desc 'Trac migration script'
   task :migrate_from_trac => :environment do