code: function hashToken(token, done) {
    return bcrypt.genSalt(10, function(genSaltErr, salt) {
      if (genSaltErr) {
        return done(genSaltErr);
      }
  
      bcrypt.hash(token, salt, done);
    });
  }
docs: Hash a token. We shall not store the token in plain text for security
  purposes.
  
  @param {String} token
  @param {Function} done - done(err, hash)