added BookForm in forms.py

bellapanghulan_reading/bookshelf/forms.py

 from django import forms
 from django.forms import ModelForm
-from .models import Author
+from .models import Author, Books
 
 class AuthorForm(ModelForm):
     class Meta:
         model = Author
-        fields = '__all__'
\ No newline at end of file
+        fields = '__all__'
+
+class BookForm(ModelForm):
+    class Meta:
+        model = Books
+        fields = '__all__'
+