ESP8266 Sleep + Interrupt

I want to make a door contact sensor that will alert when the door is open, wired up to an ESP8266 (well, an Arduino HUZZAH which uses that chip).

I figured out how to put the ESP8266 to sleep using the deepSleep command, but I can't figure out how to wake it up in response to a voltage change on a pin.

Any ideas?

Thanks!

Have you read the Sleep tutorial?