Increase borrow count on borrowing. Advances #10, #11.

biscuit/apps/exlibris/views.py

@@ -274,6 +274,7 @@ def person_borrow(request: HttpRequest) -> HttpResponse:
                     continue
 
                 book_copy.borrower = person
+                book_copy.borrow_count = book_copy.borrow_count + 1
                 book_copy.save()
 
                 messages.success(request, _('Book %s borrowed to %s.') % (book_copy.book.title, person))