Date type instead of string for datetime fields

[ppaskaris]

Greetings,

I really like the simplicity of this package, but I was wondering: is there a particular reason that this uses strings for the deleted and visible fields?

Using a date field would allow for adding a TTL Index to the deleted field, enabling the database to automatically clean up old messages.

[TomKaltz]

+1

[ianitsky]

+1