Went back to loading contacts one at a time with Javascript.

* Re-added contact fetching script and the _contact.erb partial.
* Reformatted Twilio numbers to add '+1' or '1' depending on length.
WIP adding tests on crush spec and reverted message model to exchange, changed schema
Restructured database and added testing specs.

* Added a phone table corresponding to an actual phone number. Crushes
  is now a join table between phone numbers and users.
* Added pin # to exchanges and next pin # to phones. Every exchange for
  a given phone # is assigned a unique pin number. That way, we can
  track down what user a crush is responding to.
* Added uniqueness checks at the database and model levels.
* Added a new user spec.
* Deleted Message model.