Add possibility of customizing (appending) emails. Additionally #37

[webknjaz]

$sbj.

Related: #37.

[cleac]

Very informative message 😃

The purpose of issue is that sometimes we need to send custom emails with some reminders. E.g. Don't forget to take your id to the next event.

I just didn't understand - should I implement the email and the UI for it? 'Cause then the task becomes more complicated and less related to #37

[webknjaz]

I guess, you should design email templates making them easily inheritable.

[cleac]

Then I see why they are related

[cleac]

Will do while doing #37