implemented ratings, fixes

app/server/graphql/resolvers/bookChapterDelete.ts

@@ -13,12 +13,29 @@ export async function BookChapterDeleteResolver(
   ensureIdentity(identity);
   const model = await prisma.bookChapter.findUniqueOrThrow({
     where: { id },
-    select: { book: { select: { id: true, authorId: true } } }
+    select: {
+      sequenceNumber: true,
+      book: { select: { id: true, authorId: true } }
+    }
   });
   if (identity.id !== model.book.authorId) throw new Error('Operation is not permitted.');
 
   await prisma.bookChapter.delete({ where: { id } });
 
+  await prisma.bookChapter.updateMany({
+    where: {
+      bookId: model.book.id,
+      sequenceNumber: {
+        gt: model.sequenceNumber
+      }
+    },
+    data: {
+      sequenceNumber: {
+        decrement: 1
+      }
+    }
+  });
+
   await updateBookStats(model.book.id);
   const book = await prisma.book.findUniqueOrThrow({ where: { id: model.book.id } });
   return toBookSchema(book, { req, res, identity });