rails binary tree and referral

Hi, i have an application and that is working clear but i wanna add multi level marketing binary tree module to my application.

i created binarytree page and also created add_to_column to members as below
parent_id:string
left_id:string
right_id:string
referral_by_id:string
added_by_id:string

then i did migrated to database

also already generated current_user.sn for referral before migrate

how can i make to these on binarytree page
current_user = parent or if click to user of binary tree it will be parent then show tree of them
left_id and right_id need select for tree from added_by_id
referral_by_id button with checker

i wanna mean binary tree page need referral button for add referrer if user added referrer buton will visible automaticly because all user can add one referrer
also how can i make referral_link for example "www.domain.com/signup with referral id"(referral_by_id = current_user.sn = 8 digits )
if can anybody help please?
kindly thank's
Regards