Rechargable battey and charger on Teensy-like board?

Greetings,

I want to put a small rechargeable battery with charger on a Teensy-like board to keep data in RAM and have it charge when it is plugged into USB port.

Something like this added to Teensy http://www.theledart.com/products/lir24 … ry-charger

Anyone have schematics for that?

Thanks