Add OWNERS file to gatekeeperd

Test: Yes, that would be nice, wouldn't it?
Change-Id: I4116c2546bbc15ef5edb90867ed156637bb125c6
diff --git a/gatekeeperd/OWNERS b/gatekeeperd/OWNERS
new file mode 100644
index 0000000..9c99c6e
--- /dev/null
+++ b/gatekeeperd/OWNERS
@@ -0,0 +1,2 @@
+swillden@google.com
+jdanis@google.com