add default group

src/main/resources/bootstrap.properties

@@ -50,6 +50,7 @@ server.undertow.max-http-post-size=83886080
 spring.servlet.multipart.max-file-size=100MB
 spring.servlet.multipart.max-request-size=1000MB
 dubbo.protocol.dubbo.payload=83886080
+dubbo.registry.group=
 
 hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=30000
 #hystrix.command.default.circuitBreaker.sleepWindowInMilliseconds=100000