[feature request] support cloud functions (or include examples)

[goleary]

This project looks awesome for hitting the ground running use twitter webhooks!

That said it seems best if you plan to have a persistent express instance.

Webhooks are a great use for cloud functions, so it would awesome to see this project support cloud functions and/or provide examples for popular cloud function frameworks (I'm personally most familiar with firebase cloud functions)

[Technical-13]

Apparently this library isn't available for use with repl.it either.