add possibility to delete a book

src/main/java/dj/personal/website/book/BookController.java

@@ -29,4 +29,10 @@ public Collection<Book> findAll() {
 	public Book save(@RequestBody Book book) {
 		return bookService.save(book);
 	}
+
+	@DeleteMapping(path = "/{isbn}")
+	@RolesAllowed(Role.ADMIN)
+	public void delete(@PathVariable Long isbn){
+		bookService.deleteByIsbn(isbn);
+	}
 }

src/main/java/dj/personal/website/book/BookRepository.java

@@ -4,4 +4,5 @@
 import org.springframework.data.jpa.repository.JpaRepository;
 
 interface BookRepository extends JpaRepository<Book, Long> {
+    void deleteByIsbn(Long isbn);
 }

src/main/java/dj/personal/website/book/BookService.java

@@ -30,4 +30,8 @@ public Collection<Book> getBooks() {
 	public Book save(Book book) {
 		return bookRepository.save(book);
 	}
+
+	public void deleteByIsbn(Long isbn) {
+		bookRepository.deleteByIsbn(isbn);
+	}
 }