diff --git a/fitapp/migrations/0001_initial.py b/fitapp/migrations/0001_initial.py
index 926b26d..b37f9bc 100644
--- a/fitapp/migrations/0001_initial.py
+++ b/fitapp/migrations/0001_initial.py
@@ -42,7 +42,7 @@ class Migration(migrations.Migration):
                 ('fitbit_user', models.CharField(unique=True, max_length=32)),
                 ('auth_token', models.TextField()),
                 ('auth_secret', models.TextField()),
-                ('user', models.OneToOneField(to=settings.AUTH_USER_MODEL)),
+                ('user', models.OneToOneField(to=settings.AUTH_USER_MODEL,on_delete=models.CASCADE)),
             ],
             options={
             },
@@ -55,13 +55,13 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name='timeseriesdata',
             name='resource_type',
-            field=models.ForeignKey(to='fitapp.TimeSeriesDataType'),
+            field=models.ForeignKey(to='fitapp.TimeSeriesDataType',on_delete=models.CASCADE),
             preserve_default=True,
         ),
         migrations.AddField(
             model_name='timeseriesdata',
             name='user',
-            field=models.ForeignKey(to=settings.AUTH_USER_MODEL),
+            field=models.ForeignKey(to=settings.AUTH_USER_MODEL,on_delete=models.CASCADE),
             preserve_default=True,
         ),
         migrations.AlterUniqueTogether(
diff --git a/fitapp/migrations/0006_help_text.py b/fitapp/migrations/0006_help_text.py
index 630106c..c889bcd 100644
--- a/fitapp/migrations/0006_help_text.py
+++ b/fitapp/migrations/0006_help_text.py
@@ -20,12 +20,12 @@ class Migration(migrations.Migration):
         migrations.AlterField(
             model_name='timeseriesdata',
             name='resource_type',
-            field=models.ForeignKey(help_text=b'The type of time series data', to='fitapp.TimeSeriesDataType'),
+            field=models.ForeignKey(help_text=b'The type of time series data', to='fitapp.TimeSeriesDataType', on_delete=models.CASCADE),
         ),
         migrations.AlterField(
             model_name='timeseriesdata',
             name='user',
-            field=models.ForeignKey(help_text=b"The data's user", to=settings.AUTH_USER_MODEL),
+            field=models.ForeignKey(help_text=b"The data's user", to=settings.AUTH_USER_MODEL, on_delete=models.CASCADE),
         ),
         migrations.AlterField(
             model_name='timeseriesdata',
@@ -65,6 +65,6 @@ class Migration(migrations.Migration):
         migrations.AlterField(
             model_name='userfitbit',
             name='user',
-            field=models.OneToOneField(to=settings.AUTH_USER_MODEL, help_text=b'The user'),
+            field=models.OneToOneField(to=settings.AUTH_USER_MODEL, help_text=b'The user', on_delete=models.CASCADE),
         ),
     ]
diff --git a/fitapp/models.py b/fitapp/models.py
index ad81bc7..a18327c 100644
--- a/fitapp/models.py
+++ b/fitapp/models.py
@@ -1,16 +1,16 @@
 from django.conf import settings
 from django.db import models
-from django.utils.encoding import python_2_unicode_compatible
 
 
 UserModel = getattr(settings, 'AUTH_USER_MODEL', 'auth.User')
 
 
-@python_2_unicode_compatible
 class UserFitbit(models.Model):
     """ A user's fitbit credentials, allowing API access """
     user = models.OneToOneField(
-        UserModel, help_text='The user')
+        UserModel, 
+        help_text='The user',
+        on_delete=models.CASCADE)
     fitbit_user = models.CharField(
         max_length=32, unique=True, help_text='The fitbit user ID')
     access_token = models.TextField(help_text='The OAuth2 access token')
@@ -92,9 +92,12 @@ class TimeSeriesData(models.Model):
     https://dev.fitbit.com/docs/body/#body-time-series
     """
 
-    user = models.ForeignKey(UserModel, help_text="The data's user")
+    user = models.ForeignKey(UserModel, 
+                             help_text="The data's user",
+                            on_delete=models.CASCADE)
     resource_type = models.ForeignKey(
-        TimeSeriesDataType, help_text='The type of time series data')
+        TimeSeriesDataType, help_text='The type of time series data',
+                            on_delete=models.CASCADE)
     date = models.DateField(help_text='The date the data was recorded')
     value = models.CharField(
         null=True,
diff --git a/fitapp/utils.py b/fitapp/utils.py
index 80c79e3..1cb8ca8 100644
--- a/fitapp/utils.py
+++ b/fitapp/utils.py
@@ -35,7 +35,7 @@ def is_integrated(user):
 
     :param user: A Django User.
     """
-    if user.is_authenticated() and user.is_active:
+    if user.is_authenticated and user.is_active:
         return UserFitbit.objects.filter(user=user).exists()
     return False
 
diff --git a/fitapp/views.py b/fitapp/views.py
index 4915a8b..f61a5b4 100644
--- a/fitapp/views.py
+++ b/fitapp/views.py
@@ -6,7 +6,7 @@
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.signals import user_logged_in
 from django.core.exceptions import ImproperlyConfigured
-from django.core.urlresolvers import reverse
+from django.urls import reverse
 from django.dispatch import receiver
 from django.http import HttpResponse, HttpResponseServerError, Http404
 from django.shortcuts import redirect, render
@@ -147,7 +147,7 @@ def complete(request):
 def create_fitbit_session(sender, request, user, **kwargs):
     """ If the user is a fitbit user, update the profile in the session. """
 
-    if user.is_authenticated() and utils.is_integrated(user) and \
+    if user.is_authenticated and utils.is_integrated(user) and \
             user.is_active:
         fbuser = UserFitbit.objects.filter(user=user)
         if fbuser.exists():
@@ -421,7 +421,7 @@ def get_data(request, category, resource):
         return make_response(104)
 
     fitapp_subscribe = utils.get_setting('FITAPP_SUBSCRIBE')
-    if not user.is_authenticated() or not user.is_active:
+    if not user.is_authenticated or not user.is_active:
         return make_response(101)
     if not fitapp_subscribe and not utils.is_integrated(user):
         return make_response(102)