Track mail opened and link clicked with mailmerge

[robbiedood]

Dear apps-script-samples friends,

The example of mailmerge in gmail is really useful to send a bulk personalized email.

Next, we are thinking to track email's open rate and its click rate on any link inside an email.

We were wondering if there are already similar functions in this github (or any reference we could learn). Hope to get your expertise on that.

Best, -- Luke