README.md in signer-1.0.0 vs README.md in signer-1.1.0

@@ -25,10 +25,10 @@
 
 signer.document.xpath("//a:To", { "a" => "http://www.w3.org/2005/08/addressing" }).each do |node|
   signer.digest!(node)
 end
 
-signer.sign!
+signer.sign!(:security_token => true)
 
 signer.to_xml
 ```
 
 ## Usage with Savon