Ask HN: Open Source my web app or Sell it on Flippa?

I built this rails app at www.ubercamp.net and haven't had time to do any marketing or maintain it. Instead of it sitting there doing nothing, should I sell it on flippa.com or open source it on github? If I do sell, how would I even price it? It's a fully functioning app with subscription management and stripe, new relic, google analytics and active admin integration but it has ZERO revenue because I never promoted it. Thoughts?