Set gmail as ghost mail sender

It’s in a different place to set user subscribe email sender compared to the newsletter setting on the admin page. The settings should be put into the ghost conf file. If you use docker as I do, you can put the settings in env variables.

Since the register email is to a single person, we don’t need to use Mailgun as the sender which is suitable for sending bulk emails with an initial free limit. And if you use the free plan, the domain of the email cannot be customized, so I suggest using a personal email like gmail as the sender. It’s totally supported by ghost since ghost uses Nodemailer at backend. Nodemailer supports gmail.

Steps are below. (hey, subscribe to see the full steps and the mail sent to you :)