In-app notifications

[sshanzel]

I think it would be nice to have a notification feed to easily manage updates inside the app.

As a writer, I want to immediately get notified when someone upvoted/commented on my article.

As a user, I want to get notified when people upvoted/commented on my comments. It would be nice to know also if my comment got featured.

In relation to this request, it would be lovely to get notified as well.