Already have an android app, want to add "HIKE" like referral.

Please check my app: [login to view URL] what I want to do it add HIKE like referral program where in a user invites (shares a unique link via any source) and once a user downloads through that link. the first user gets credited with 20 points. ( as in HIKE example) want a similar referral program for my app. Only serious and experienced people who are interested to do this message me directly with days required, and how will you go about it. after seeing your previous work we can agree upon a pay & start working.