def populate_approved_followers_feeds(user_id, post_id, timestamp):
    """Fan out a post_id to all the users approved followers."""
    # Get a list of ALL users who are following a user
    followers = r.zrange(k.USER_APPROVED.format(user_id), 0, -1)
    # This is not transactional as to not hold Redis up.
    for follower_id in followers:
        # Add the pid to the list
        r.zadd(k.USER_FEED.format(follower_id), {str(post_id): timestamp})
        # Stop followers feeds from growing to large, doesn't matter if it
        # doesn't exist
        r.zremrangebyrank(k.USER_FEED.format(follower_id), 0, -1000)