Allows you to setup a GitHub repository to send out SMS messages on git pushes.
Currently the SMS message is built to say:

    "#{payload['pusher']['name']} has pushed #{payload['commits'].size} commit(s) to #{payload['repository']['name']}"

Install Notes
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1. Signup for a Twilio account at http://www.twilio.com/try-twilio?home-page
2. You can find your account_sid and auth_token on your account page at https://www.twilio.com/user/account
3. from_phone must be a "Twilio phone number enabled for SMS. Only phone numbers or short codes purchased from Twilio work here"
4. to_phone is the "destination phone number. Format with a '+' and country code e.g., +16175551212 (E.164 format)."
5. Check master_only if you only want to receive updates for master.

