referral_system for autobiz

1. Create referral_bonus table

1.1. table information

1.2. plan_id

1.2.1. airtime_percent

1.2.1.1. data_percent

2. At billing class

2.1. At successful transaction, we will check the userid of the buyer and the same timecheck if the buyer used referral code, if yes, we will check the detail of the user his/her referral code was used, checking his current plan and also using that to get the information setup at the referral_bonus_table inorder to do the crediting.

3. steps to work on it

3.1. add setting to general_settings to activate/deactivate referral block