use settings.AUTH_USER_MODEL instead of User in foreign keys

app/models/preset.py

@@ -1,6 +1,6 @@
 import logging
 
-from django.contrib.auth.models import User
+from django.conf import settings
 from django.contrib.postgres.fields import JSONField
 from django.db import models
 from django.utils import timezone
@@ -10,7 +10,7 @@ logger = logging.getLogger('app.logger')
 
 
 class Preset(models.Model):
-    owner = models.ForeignKey(User, blank=True, null=True, on_delete=models.CASCADE, help_text="The person who owns this preset")
+    owner = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.CASCADE, help_text="The person who owns this preset")
     name = models.CharField(max_length=255, blank=False, null=False, help_text="A label used to describe the preset")
     options = JSONField(default=list, blank=True, help_text="Options that define this preset (same format as in a Task's options).",
                                validators=[validate_task_options])

app/models/project.py

@@ -1,6 +1,6 @@
 import logging
 
-from django.contrib.auth.models import User
+from django.conf import settings
 from django.db import models
 from django.db.models import Q
 from django.db.models import signals
@@ -18,7 +18,7 @@ logger = logging.getLogger('app.logger')
 
 
 class Project(models.Model):
-    owner = models.ForeignKey(User, on_delete=models.PROTECT, help_text="The person who created the project")
+    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, help_text="The person who created the project")
     name = models.CharField(max_length=255, help_text="A label used to describe the project")
     description = models.TextField(default="", blank=True, help_text="More in-depth description of the project")
     created_at = models.DateTimeField(default=timezone.now, help_text="Creation date")