DATACOUCH-314 - Adopt to ReactiveCrudRepository.deleteById(Publisher).

Related ticket: DATACMNS-1063.

Original Pull Request: #147

src/main/java/org/springframework/data/couchbase/repository/support/SimpleReactiveCouchbaseRepository.java

@@ -42,6 +42,7 @@ import reactor.core.publisher.Mono;
  *
  * @author Subhashni Balakrishnan
  * @author Mark Paluch
+ * @author Christoph Strobl
  * @since 3.0
  */
 public class SimpleReactiveCouchbaseRepository<T, ID extends Serializable> implements ReactiveCouchbaseRepository<T, ID> {
@@ -191,6 +192,13 @@ public class SimpleReactiveCouchbaseRepository<T, ID extends Serializable> imple
         return mapMono(operations.remove(id.toString()).map(res -> Observable.<Void>empty()).toSingle());
     }
 
+    @Override
+    public Mono<Void> deleteById(Publisher<ID> publisher) {
+        Assert.notNull(publisher, "The given id must not be null!");
+        return Mono.from(publisher).flatMap(
+                this::deleteById);
+    }
+
     @SuppressWarnings("unchecked")
     @Override
     public Mono<Void>  delete(T entity) {