2 files changed, 3 insertions, 3 deletions
diff --git a/app/books/build.py b/app/books/build.py
index 6743e89..35fdb19 100644
--- a/app/books/build.py
+++ b/app/books/build.py
@@ -1,5 +1,5 @@
 import os
-from django.core.urlresolvers import reverse
+from django.urls import reverse
 from builder.base import BuildNew
 
 
diff --git a/app/books/models.py b/app/books/models.py
index 4362bc9..f888480 100644
--- a/app/books/models.py
+++ b/app/books/models.py
@@ -1,5 +1,5 @@
 from django.db import models
-from django.core.urlresolvers import reverse
+from django.urls import reverse
 from django.utils.encoding import force_text
 from django.conf import settings
 from django.template.defaultfilters import slugify
@@ -69,7 +69,7 @@ class Book(models.Model):
 
 
 class BookHighlight(models.Model):
-    book = models.ForeignKey(Book)
+    book = models.ForeignKey(Book, on_delete=models.CASCADE)
     page = models.PositiveSmallIntegerField(null=True)
     location = models.CharField(max_length=200, blank=True, null=True)
     date_added = models.DateTimeField()