I have been using Trello for work, but now have a personal board with friends for books we read. We have a column for book recommendations but we don't want it to get absurdly long. We were thinking that perhaps after 30 days any cards in this list could auto archive to keep our list in control. Can you do this? I checked google and the community boards...and I only found a power up called Card aging, but it doesn't sound like it disappears just fades but stays on your list.