ETag support

[dkam]

Hi there,
Are you interested in adding etag support? I was thinking of adding an etag attribute to FoundFile, calculating sha1 hash during initialisation, then adding an etag( @file.etag ) to the controller.

Happy to send a pull request if you're interested.

Cheers,
Dan

[rob-murray]

Yeah happy with that - feel free to create a PR if you want.