checkin now flatbuffer
diff --git a/third_party/flatbuffers b/third_party/flatbuffers
new file mode 160000
index 0000000..6beb9f4
--- /dev/null
+++ b/third_party/flatbuffers
@@ -0,0 +1 @@
+Subproject commit 6beb9f49cb44095c4c17be43f13906c6eb09d7c7