[Melbourne-pm] Another Data::Token example

[Scott Penrose]

As I was signing up to a web site today I realised there was another  
example to add for Tokens - Invitations. Gmail in the early days had  
tokens to allow you to sign up. You got given a few.

These have all the same requirements as authentication tokens - in  
particular checked against a database etc. However they tend to be a  
lot shorter - e.g. one I used today is wzCWPFnw0d

It would be a mistake though to be too general, it would probably be  
better to create Data::Token::Simple if that was required.

Scott