created app bookshelf and implemented models

rachpurisima_reading/bookshelf/admin.py

+from django.contrib import admin
+
+# Register your models here.

rachpurisima_reading/bookshelf/apps.py

+from django.apps import AppConfig
+
+
+class BookshelfConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'bookshelf'

rachpurisima_reading/bookshelf/models.py

+from django.db import models
+from django.core.validators import MinLengthValidator, RegexValidator
+
+class Author(models.Model):
+
+    first_name = models.CharField(max_length=100)
+    last_name = models.CharField(max_length=100)
+    age = models.IntegerField()
+    nationality = models.CharField(max_length=100)
+    bio = models.TextField()
+
+    def __str__(self):
+        return '{} {}'.format(self.first_name, self.last_name)
+
+class Books(models.Model):
+
+    title = models.CharField(max_length=100)
+    author = models.ForeignKey(Author,on_delete=models.CASCADE,default="")
+    publisher = models.CharField(max_length=100)
+    year_published = models.IntegerField(validators=[MinValueValidator(0),MaxValueValidator(2023)])
+    ISBN = models.CharField(primary_key=True, max_length=13,validators=[MinLengthValidator(13), RegexValidator(r'^\d{1,10}$')])
+
+    def __str__(self):
+        return '{}'.format(self.title)

rachpurisima_reading/bookshelf/tests.py

+from django.test import TestCase
+
+# Create your tests here.

rachpurisima_reading/bookshelf/urls.py

+from django.urls import path
+from .views import index
+
+urlpatterns = [
+    path('', index, name='index'),
+]
+# This might be needed, depending on your Django version
+app_name = "bookshelf"

rachpurisima_reading/bookshelf/views.py

+from django.shortcuts import render
+from django.http import HttpResponse
+
+# Create your views here.
+
+def index(request):
+    return HttpResponse('bookshelf view')

rachpurisima_reading/rachpurisima_reading/settings.py

@@ -40,6 +40,8 @@ INSTALLED_APPS = [
     'django.contrib.sessions',
     'django.contrib.messages',
     'django.contrib.staticfiles',
+
+    'bookshelf',
 ]
 
 MIDDLEWARE = [

rachpurisima_reading/rachpurisima_reading/urls.py

@@ -14,8 +14,9 @@ Including another URLconf
     2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
 """
 from django.contrib import admin
-from django.urls import path
+from django.urls import path, include
 
 urlpatterns = [
     path('admin/', admin.site.urls),
+    path('',include('bookshelf.urls', namespace='bookshelf')),
 ]