Redmine

I am just getting started with Redmine to manage projects on my Farm. I have a group of contractors I'd like to record their time in the system but they are resisting, as they aren't very computer literate. Other than recording their passwords and logging in as them to track their hours, is there a way I can do it while logged in as the site admin? Right now it seems I can't log hours on behalf of other users. Any suggestions?