fredjean/middleman-s3_sync — pull request #4 by willkoehler (2013-03-21 01:35:22+00:00)
Title: Set cache-control and expires headers to improve browser caching.

I'm assuming most assets deployed with Middleman will use an asset hash. So setting expiration for 1 year should be safe. This cache expiration is based on the asset_sync gem's cache headers.