remove node when one leaves
diff --git a/sync-demo.pro b/sync-demo.pro
index a12f970..f65fbdd 100644
--- a/sync-demo.pro
+++ b/sync-demo.pro
@@ -20,6 +20,7 @@
 
 QMAKE_CXXFLAGS *= -g 
 QMAKE_CFLAGS *= -g 
+LIBS += -lboost_system-mt
 
 CONFIG += console