How to get the last push date or file modification date when deploying to Heroku?

What is the easiest way to get the latest file modification date (latest of all files, not a single one) or last push date to Heroku?

I would like to put on the foote开发者_如何学运维r: "Last site update on July 28, 2011"

Working in Rails 3.

Thanks!

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You can look at the output of git log

git clone -o heroku git@heroku.com:appname.git
cd appname
git log