Remove Sync example, link to objectbox-sync-examples repo

Author: greenrobot-team

objectbox/Makefile

@@ -15,4 +15,3 @@ depend:			## Build dependencies
 integration-test:	## Execute integration tests
 	./tool/integration-test.sh example/flutter/objectbox_demo
 	./tool/integration-test.sh example/flutter/objectbox_demo_relations
-	./tool/integration-test.sh example/flutter/objectbox_demo_sync

objectbox/example/README.md

@@ -1,16 +1,16 @@
-ObjectBox Examples
-==========================
+# ObjectBox Flutter SDK Examples
 
-There are several example apps and tutorials available:
+Note: [A Flutter example app](https://github.com/objectbox/objectbox-sync-examples/tree/main/tasks/client-flutter)
+that uses [Sync](https://objectbox.io/sync/) is available in the objectbox-sync-examples repo.
+
+There are several example apps and tutorials available in this repository:
 
-* [vectorsearch_cities](dart-native/vectorsearch_cities): a Dart Native example app using Vector
-  Search to find neighbors of cities.
 * [objectbox_demo_relations](flutter/objectbox_demo_relations): our main Flutter example app showing 
   all basics and how to use relations.
-* [event_management_tutorial](flutter/event_management_tutorial): an event management Flutter app 
+* [objectbox_demo](flutter/objectbox_demo): a very basic Flutter example app.
+* [vectorsearch_cities](dart-native/vectorsearch_cities): a Dart Native example app using Vector
+  Search to find neighbors of cities.
+* [event_management_tutorial](flutter/event_management_tutorial): an event management Flutter app
   based on our video tutorial on using relations.
-* [objectbox_demo](flutter/objectbox_demo): a basic Flutter example app.
-* [objectbox_demo_sync](flutter/objectbox_demo_sync): a basic Flutter example app with 
-  [Sync](https://objectbox.io/sync/) enabled.
 
 **To learn how to use ObjectBox continue with the [Getting Started](https://docs.objectbox.io/getting-started) guide.**

objectbox/example/flutter/objectbox_demo_sync/.gitignore

@@ -1,24 +1,3 @@
 # objectbox_demo_sync
 
-## Getting Started with ObjectBox Sync in Flutter / Dart
-
-This project contains the Flutter version of the Sync example from the [objectbox-examples](https://github.com/objectbox/objectbox-examples) repository.
-
-You need to have a Sync Trial and run the Sync Server to run the demo --> Apply for the [Sync Trial here](https://objectbox.io/sync/).
-
-Also, do check out the [Sync Docs](https://sync.objectbox.io/).
-
-The basic steps to get this demo running (assuming you have a working Flutter setup):
-
-```
-# Set up project, get latest dependencies
-flutter pub upgrade
-
-# Generate model and code files for ObjectBox
-dart run build_runner build
-
-# Run the app in debug mode
-flutter run
-```
-
-Optional: depending on your setup you might have to adjust the Sync server address in [objectbox.dart](/lib/objectbox.dart).
+This example has [moved to the objectbox-sync-examples repository](https://github.com/objectbox/objectbox-sync-examples/tree/main/tasks/client-flutter).