Salesforce contact creation PoC

This uses a salesforce/heroku developed gem, databasedotcom, to create a Salesforce contact when a user confirms their account on Beyond Z.
I think this is fine for the PoC, but in future passes we should probably start a separate controller/helper for all salesforce related things and handle all salesforce specific logic inside there, instead of scattering checks on the username (which is nonobvious why we do it) all the all over the calling code.