[css-rhythm] Add acknowledgements

kojiishi · kojiishi · commit 279121d4d5d4 · 2017-11-07T19:18:26.000+09:00
diff --git a/css-rhythm-1/Overview.bs b/css-rhythm-1/Overview.bs
@@ -506,4 +506,6 @@ Acknowledgments {#acks}
 	Florian Rivoal,
 	Hiroshi Sakakibara,
 	Alan Stearns,
+	Masataka Yakura,
+	PixelGrid Inc.,
 	and the CSS Working Group members.
