Guest.beforeCreate(function(guest) {
  bcrypt.genSalt(10, function(error, salt) {
    if (error) { return error }
    bcrypt.hash(guest.password, salt, null, function(error, hash) {
      if (error) { return error }
      guest.password = hash;
    })
  })
});

Guest.beforeCreate(function(guest) {
  guest.password = "something";
});

Guest.beforeCreate(function(guest) {
  bcrypt.genSalt(10, function(error, salt) {
    if (error) { return error }
    bcrypt.hash(guest.password, salt, null, function(error, hash) {
      if (error) { return error }
      guest.password = hash;
      guest.save(); // Added this line to get it to save.
    })
  })
});