bcrypt-ruby is now known as bcrypt

The bcrypt-ruby gem has changed to simply bcrypt. This change gets rid of the following message upon installing omniauth-identity:


     Post-install message from bcrypt-ruby:

     #######################################################

     The bcrypt-ruby gem has changed its name to just bcrypt.  Instead of
     installing `bcrypt-ruby`, you should install `bcrypt`.  Please update your
     dependencies accordingly.

     #######################################################