Add missing readme link.

jmdobry · jmdobry · commit f37ff1522bb9 · 2016-06-22T16:02:13.000-07:00
diff --git a/functions/README.md b/functions/README.md
@@ -30,3 +30,4 @@ environment.
 * [Logging](log/)
 * [Modules](module/)
 * [OCR (Optical Character Recognition)](ocr/)
+* [SendGrid](sendgrid/)
