Added get_absolute_url function to all models

enzosalvador_reading/bookshelf/models.py

 from django.db import models
+from django.urls import reverse
 
 class Author(models.Model):
     first_name = models.CharField(max_length = 50, default = "")
@@ -9,6 +10,9 @@ class Author(models.Model):
 
     def __str__(self):
         return self.last_name
+    
+    def get_absolute_url(self):
+        return reverse('bookshelf:author-details', kwargs={'pk':self.pk})
 
 class Books(models.Model):
     title = models.CharField(max_length = 50, default = "")
@@ -20,3 +24,6 @@ class Books(models.Model):
 
     def __str__(self):
         return self.title
+    
+    def get_absolute_url(self):
+        return reverse('bookshelf:book-details', kwargs={'pk':self.pk})