Adds more fields to book data

fedireads/templates/edit_book.html

@@ -40,7 +40,7 @@
 
     <h3>Book Identifiers</h2>
     <div>
-        <p><label for="id_isbn">ISBN:</label> {{ form.isbn }} </p>
+        <p><label for="id_isbn">ISBN 13:</label> {{ form.isbn_13 }} </p>
         <p><label for="id_fedireads_key">Fedireads key:</label> {{ form.fedireads_key }} </p>
         <p><label for="id_openlibrary_key">Openlibrary key:</label> {{ form.openlibrary_key }} </p>
         <p><label for="id_librarything_key">Librarything key:</label> {{ form.librarything_key }} </p>