I can only agree what all others have said. This should be a build in feature of Shopify!
Time for the monthly bump to request this feature. Seems very straight forward.
+1 this should definitely be a core offering, please can you let us know where in the queue this stands Shopify?
I don't think this is going to move much since it's listed as "solved" Let's try and repost it with the concern that we shouldn't have to pay for an app to do this?
I might also try tweeting @ Shopify.