How can we set Scroll Rect vertical position to 0 to show latest item?

[SourabhPTW]

I am using it to created Chat system and below is my requirements.

1. The Chat Panel should have an infinite scroll so Users can see the Chat Histories.
2. New Message should be at the bottom of ViewPort.
3. Users can't scroll down to beyond the latest Message.
4. Users can't scroll down beyond Last Chat History.