Misago/misago/readtracker/models.py

from django.conf import settings
from django.db import models
from django.utils import timezone


class PostRead(models.Model):
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
    )
    category = models.ForeignKey(
        'misago_categories.Category',
        on_delete=models.CASCADE,
    )
    thread = models.ForeignKey(
        'misago_threads.Thread',
        on_delete=models.CASCADE,
    )
    post = models.ForeignKey(
        'misago_threads.Post',
        on_delete=models.CASCADE,
    )
    last_read_on = models.DateTimeField(default=timezone.now)