This works with mailgun.AddRecipientAndVariables, so we can safely send
emails to a large number of recipients beyond Mailgun's 1,000-recipient
limit.
Ref T856
This adds beginning email subscription functionality, with only MySQL support,
Mailgun support, and incomplete support for private instances. It includes
database changes, so run:
writefreely db migrate
to use this feature.
Ref T856
Matt Baer