Post model

from django.db import models
from django.db.models.signals import post_delete, pre_save
from django.dispatch import receiver
from django.contrib.auth.models import AbstractBaseUser, BaseUserManager
from django.conf import settings
from django.utils.text import slugify

# get post upload folder
def photo_directory_path(instance, filename):
    return 'posts/{0}/{1}'.format(instance.author, filename)

class Post(models.Model):
    author = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete= models.CASCADE, related_name='posts')

    title = models.CharField(max_length=200)
    description = models.TextField()
    photo = models.ImageField(upload_to=photo_directory_path, blank=True)
    likes = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name='likes', blank=True)
    picked = models.BooleanField(default=False)

    slug = models.SlugField(max_length=200, blank=True)
    updated_on = models.DateTimeField(auto_now= True)
    created_on = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-created_on']

    def __str__(self):
        return self.title

# delete post picture
@receiver(post_delete, sender=Post)
def file_cleanup(sender, instance, **kwargs):
    if instance.photo:
        os.remove(instance.photo.path)

# generate slug for posts
@receiver(pre_save, sender=Post)
def slug_generator(sender, instance, *args, **kwargs):
    instance.slug = f'{slugify(instance.title)}-{int(time.time())}'