Revert "Revert "updated documentation to include rootfs_uri in place of image""
Revert "Revert "updated documentation to include rootfs_uri in place of image""

This reverts commit df44dd72856dda716d7dc00a80be375d41d94616.

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse