code: function (invite, cb) {
        var id = api.keys.sync.id()
        var data = ref.parseInvite(invite)
        api.contact.async.followerOf(id, data.key, function (_, follows) {
          if (follows) console.log('already following', cb())
          else console.log('accept invite:' + invite, accept(invite, cb))
        })
      }
docs: like invite, but check whether we already follow them first