diff --git a/vendor/symposion/schedule/models.py b/vendor/symposion/schedule/models.py
index 613d1d4c1f48cb64bb8975c5fe2f1058b0854523..6698eb25649805a10c4c6d1ccb1f508e3d88668d 100644
--- a/vendor/symposion/schedule/models.py
+++ b/vendor/symposion/schedule/models.py
@@ -1,7 +1,7 @@
 import datetime
 
 from django.core.exceptions import ObjectDoesNotExist
-from django.contrib.auth.models import User
+from django.contrib.auth import get_user_model
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
@@ -11,11 +11,17 @@ from symposion.proposals.models import ProposalBase
 from symposion.conference.models import Section
 from symposion.speakers.models import Speaker
 
+User = get_user_model()
+
 
 class Schedule(models.Model):
     objects = DefaultSelectRelatedManager()
 
-    section = models.OneToOneField(Section, verbose_name=_("Section"))
+    section = models.OneToOneField(
+        Section,
+        verbose_name=_("Section"),
+        on_delete=models.CASCADE,
+    )
     published = models.BooleanField(default=True, verbose_name=_("Published"))
     hidden = models.BooleanField(_("Hide schedule from overall conference view"), default=False)
 
@@ -35,7 +41,11 @@ class Day(models.Model):
     objects = DefaultSelectRelatedManager()
 
 
-    schedule = models.ForeignKey(Schedule, verbose_name=_("Schedule"))
+    schedule = models.ForeignKey(
+        Schedule,
+        verbose_name=_("Schedule"),
+        on_delete=models.CASCADE,
+    )
     date = models.DateField(verbose_name=_("Date"))
 
     def __str__(self):
@@ -53,7 +63,11 @@ class Day(models.Model):
 
 class Room(models.Model):
 
-    schedule = models.ForeignKey(Schedule, verbose_name=_("Schedule"))
+    schedule = models.ForeignKey(
+        Schedule,
+        verbose_name=_("Schedule"),
+        on_delete=models.CASCADE,
+    )
     name = models.CharField(max_length=65, verbose_name=_("Name"))
     order = models.PositiveIntegerField(verbose_name=_("Order"))
 
@@ -70,8 +84,8 @@ class Room(models.Model):
 
 class Track(models.Model):
     name = models.CharField(max_length=80, verbose_name=_("Track"))
-    room = models.ForeignKey(Room)
-    day = models.ForeignKey(Day)
+    room = models.ForeignKey(Room, on_delete=models.CASCADE)
+    day = models.ForeignKey(Day, on_delete=models.CASCADE)
 
     def __str__(self):
         return self.name
@@ -88,7 +102,11 @@ class SlotKind(models.Model):
     break, lunch, or X-minute talk.
     """
 
-    schedule = models.ForeignKey(Schedule, verbose_name=_("schedule"))
+    schedule = models.ForeignKey(
+        Schedule,
+        verbose_name=_("schedule"),
+        on_delete=models.CASCADE,
+    )
     label = models.CharField(max_length=50, verbose_name=_("Label"))
 
     def __str__(self):
@@ -103,8 +121,16 @@ class Slot(models.Model):
     objects = DefaultSelectRelatedManager()
 
     name = models.CharField(max_length=512, editable=False)
-    day = models.ForeignKey(Day, verbose_name=_("Day"))
-    kind = models.ForeignKey(SlotKind, verbose_name=_("Kind"))
+    day = models.ForeignKey(
+        Day,
+        verbose_name=_("Day"),
+        on_delete=models.CASCADE,
+    )
+    kind = models.ForeignKey(
+        SlotKind,
+        verbose_name=_("Kind"),
+        on_delete=models.CASCADE,
+    )
     start = models.TimeField(verbose_name=_("Start"))
     end = models.TimeField(verbose_name=_("End"))
     exclusive = models.BooleanField(
@@ -194,8 +220,16 @@ class SlotRoom(models.Model):
     Links a slot with a room.
     """
 
-    slot = models.ForeignKey(Slot, verbose_name=_("Slot"))
-    room = models.ForeignKey(Room, verbose_name=_("Room"))
+    slot = models.ForeignKey(
+        Slot,
+        verbose_name=_("Slot"),
+        on_delete=models.CASCADE,
+    )
+    room = models.ForeignKey(
+        Room,
+        verbose_name=_("Room"),
+        on_delete=models.CASCADE,
+    )
 
     def __str__(self):
         return "%s %s" % (self.room, self.slot)
@@ -210,11 +244,23 @@ class SlotRoom(models.Model):
 class Presentation(models.Model):
     objects = DefaultSelectRelatedManager()
 
-    slot = models.OneToOneField(Slot, null=True, blank=True, related_name="content_ptr", verbose_name=_("Slot"))
+    slot = models.OneToOneField(
+        Slot,
+        null=True,
+        blank=True,
+        related_name="content_ptr",
+        verbose_name=_("Slot"),
+        on_delete=models.CASCADE,
+    )
     title = models.CharField(max_length=100, verbose_name=_("Title"))
     abstract = models.TextField(verbose_name=_("Abstract"))
     abstract_html = models.TextField(blank=True)
-    speaker = models.ForeignKey(Speaker, related_name="presentations", verbose_name=_("Speaker"))
+    speaker = models.ForeignKey(
+        Speaker,
+        related_name="presentations",
+        verbose_name=_("Speaker"),
+        on_delete=models.CASCADE,
+    )
     additional_speakers = models.ManyToManyField(Speaker, related_name="copresentations",
                                                  blank=True, verbose_name=_("Additional speakers"))
     unpublish = models.BooleanField(
@@ -222,8 +268,18 @@ class Presentation(models.Model):
         verbose_name=_("Do not publish"),
     )
     cancelled = models.BooleanField(default=False, verbose_name=_("Cancelled"))
-    proposal_base = models.OneToOneField(ProposalBase, related_name="presentation", verbose_name=_("Proposal base"))
-    section = models.ForeignKey(Section, related_name="presentations", verbose_name=_("Section"))
+    proposal_base = models.OneToOneField(
+        ProposalBase,
+        related_name="presentation",
+        verbose_name=_("Proposal base"),
+        on_delete=models.CASCADE,
+    )
+    section = models.ForeignKey(
+        Section,
+        related_name="presentations",
+        verbose_name=_("Section"),
+        on_delete=models.CASCADE,
+    )
 
     def save(self, *args, **kwargs):
         self.abstract_html = parse(self.abstract)
@@ -256,7 +312,12 @@ class Presentation(models.Model):
 
 class Session(models.Model):
 
-    day = models.ForeignKey(Day, related_name="sessions", verbose_name=_("Day"))
+    day = models.ForeignKey(
+        Day,
+        related_name="sessions",
+        verbose_name=_("Day"),
+        on_delete=models.CASCADE,
+    )
     slots = models.ManyToManyField(Slot, related_name="sessions", verbose_name=_("Slots"))
 
     def sorted_slots(self):
@@ -318,8 +379,16 @@ class SessionRole(models.Model):
         (SESSION_ROLE_RUNNER, _("Session Runner")),
     ]
 
-    session = models.ForeignKey(Session, verbose_name=_("Session"))
-    user = models.ForeignKey(User, verbose_name=_("User"))
+    session = models.ForeignKey(
+        Session,
+        verbose_name=_("Session"),
+        on_delete=models.CASCADE,
+    )
+    user = models.ForeignKey(
+        User,
+        verbose_name=_("User"),
+        on_delete=models.CASCADE,
+    )
     role = models.IntegerField(choices=SESSION_ROLE_TYPES, verbose_name=_("Role"))
     status = models.NullBooleanField(verbose_name=_("Status"))