Referral codes, free time, and incentivizing paid members?

Does this functionality exist on Ghost to:

  • Generate, give out and track referral codes
  • Add free time to a paid subscription

Since referrals are almost always the best way to grow an audience, I’m wondering if there’s a built in way to say “If you get someone to sign up for a year, I’ll give you 3 months free!” But to give three months for free, I would need to be able to add free time to the end of an existing subscription.

Is this possible?