I’ve been struggling with adding metadata to the ActionMailer Preview-header for a while.
What I would ideally like to do is to override the following file somewhere, adding some custom metadata to the header like in the picture attached below:
Alternatively override the mailers controller to render a different template on preview:
Is it possible to easily override either of those files without having to change the base gems or similar? Would an extra initializer be needed and if so what should be included?