Add link to Eng blog post

At the time I write this, the blog post isn't published yet, but when it
does go live, I believe this will be the right URL. I'll confirm before
merging.

Change-Id: I61296ec7ed9e34f8db01b7f218f8afc962494518
Reviewed-on: https://gerrit.causes.com/26311
Reviewed-by: Joe Lencioni <joe.lencioni@causes.com>
Tested-by: Greg Hurrell <greg@causes.com>