sign up referral module

Hi,

I need a simple sign up referral module.

1) User A (each user) signs up and is given a unique referral link

2) User B sees it and signs up with the given referral link.

3) User A earns point (example 1 point) per referral.

4) User A can see his/her total points available, while admin has the right to add or deduct the point.

Drupal version: 


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