Improve read-unread post implementation

[RutuKendre]

We have posts and events tabs. All posts and events that are not opened by user should appear highlighted(just like your Facebook notifications tab). Once the user clicks on it, it should become normal. Right now the implementation is such that if the user clicks any unread post, all posts before that one are marked read automatically. Try to find a memory and speed-efficient solution for this read-unread posts thing.

[raghavpawar]

Hi, I would like to work on this issue