new: return status message from root url

Author: ludomikula

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/framework/IndexController.java

@@ -0,0 +1,18 @@
+package org.lowcoder.api.framework;
+
+import lombok.RequiredArgsConstructor;
+import org.lowcoder.api.framework.view.ResponseView;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import reactor.core.publisher.Mono;
+
+@RequiredArgsConstructor
+@RestController
+public class IndexController {
+
+    @GetMapping(value = "/", consumes = {MediaType.ALL_VALUE})
+    public Mono<ResponseView<Void>> index() {
+        return Mono.just(ResponseView.error(ResponseView.SUCCESS, "Lowcoder API is up and runnig"));
+    }
+}