Merge pull request #4182 from crweiner/automating-subusers

[Do Not Merge] Creates Automating Subusers Page

Author: Kaylyn Sigler

content/docs/for-developers/sending-email/api-getting-started.md

@@ -82,4 +82,5 @@ For more information on SendGrid and where you can go from here, check out these
 
 - [API Reference]({{root_url}}/api-reference/)
 - [Sender Authentication]({{root_url}}/ui/account-and-settings/how-to-set-up-domain-authentication/)
+- [Automating Subusers]({{root_url}}/for-developers/sending-email/automating-subusers/)
 - [How to Send Email]({{root_url}}/ui/sending-email/how-to-send-email-with-marketing-campaigns/)