Fix `501 invalid RCPT TO address provided` errors caused by usernames containing invalid characters. Example: `To: Foo,Bar <foobar@gmail.com>`.
Mailers
This directory contains mailers for sending emails. Mailers are kind of like controllers, except for generating emails instead of generating HTML.
The actual email templates live in app/views/user_mailer.
Emails are sent asynchronously using a background job. If sending the email fails, it will be retried later.
Sending emails requires a SMTP server to be configured in config/danbooru_local_config.rb. In production, Amazon SES is used to send emails.
Email templates can be previewed at http://localhost:3000/rails/mailers (assuming you're running bin/rails server on
port 3000, the default).
Example
UserMailer.welcome_user(@user).deliver_later