diff --git a/src/newsreader/accounts/models.py b/src/newsreader/accounts/models.py
index 0b2799f..18eba07 100644
--- a/src/newsreader/accounts/models.py
+++ b/src/newsreader/accounts/models.py
@@ -43,7 +43,7 @@ class User(AbstractUser):
 
     task = models.OneToOneField(
         PeriodicTask,
-        on_delete=models.SET_NULL,
+        on_delete=models.CASCADE,
         null=True,
         blank=True,
         editable=False,
diff --git a/src/newsreader/news/core/models.py b/src/newsreader/news/core/models.py
index 64028d2..28bf3fd 100644
--- a/src/newsreader/news/core/models.py
+++ b/src/newsreader/news/core/models.py
@@ -1,4 +1,5 @@
 from django.db import models
+from django.utils import timezone
 from django.utils.translation import gettext as _
 
 from newsreader.core.models import TimeStampedModel
@@ -9,7 +10,7 @@ class Post(TimeStampedModel):
     title = models.CharField(max_length=200, blank=True, null=True)
     body = models.TextField(blank=True, null=True)
     author = models.CharField(max_length=40, blank=True, null=True)
-    publication_date = models.DateTimeField(blank=True, null=True)
+    publication_date = models.DateTimeField(default=timezone.now)
     url = models.URLField(max_length=1024, blank=True, null=True)
 
     read = models.BooleanField(default=False)
@@ -18,7 +19,7 @@ class Post(TimeStampedModel):
         CollectionRule, on_delete=models.CASCADE, editable=False, related_name="posts"
     )
     remote_identifier = models.CharField(
-        max_length=500, blank=True, null=True, editable=False
+        max_length=500, editable=False, blank=True, null=True
     )
 
     def __str__(self):