birthday = models.DateField()
anniversary = models.ForeignKey(Anniversary)
address = models.ForeignKey(Address)


class Address(models.Model):
    line1 = models.CharField(max_length=150)
line2 = models.CharField(max_length=150)
postalcode = models.CharField(max_length=10)
city = models.CharField(max_length=150)
country = models.CharField(max_length=150)


class Anniversary(models.Model):
    date = models.DateField()
Foreign Key Django Model