Add default code reviewers into OWNERS

Bug: 33166666
Test: gerrit uploader
Change-Id: I9bfdec3ef3b133c0b9eaa6ed5f079ab96b93296f
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..00dad72
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,3 @@
+# Default code reviewers picked from top 3 or more developers.
+# Please update this list if you find better candidates.
+jjaggi@google.com