from django.db import models
from django.db.models.signals import post_save
from django.dispatch import receiver
from django.contrib.auth import get_user_model
from django.contrib.postgres.fields import ArrayField

class Profile(models.Model):
    user = models.OneToOneField(get_user_model(), on_delete=models.CASCADE)
    newField = ArrayField(models.CharField(max_length=16))

@receiver(post_save, sender=get_user_model())
def create_user_profile(sender, instance, created, **kwargs):
    if created:
        Profile.objects.create(user=instance)

@receiver(post_save, sender=get_user_model())
def save_user_profile(sender, instance, **kwargs):
    instance.profile.save()

current_user = User.objects.get(username=request.user)
current_user.save()

Exception Type: RelatedObjectDoesNotExist
Exception Value: User has no profile.