Don't use book absolute ids for nav

fedireads/migrations/0037_auto_20200504_0049.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.0.3 on 2020-05-04 00:49
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fedireads', '0036_auto_20200503_2007'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='author',
+            name='fedireads_key',
+        ),
+        migrations.RemoveField(
+            model_name='book',
+            name='fedireads_key',
+        ),
+    ]