Simple commit mechanism for non-technical users

I use git to manage all project artifacts, including documentation, proposals, presentations, and so on.

However, I have a hard time convincing non-technical staff to learn enough about git or to take the time to go through the effort of committing changes to a repository. So the steady stream of email attachments with "Acme Specification v3" or "final final spemco proprosal" continues.

I'd hoped there was a simple web interface that would allow a user to upload and commit a file to a repository, but I've had no luck finding one. (I've used cgit for browsing, but it is read-only).

Is anyone aware of a simple way I can have my non-technical users manage their documents against a git repository? Ideally this would involve no installation of software on their machine (unless it were compelling, for example, the Finder plugin for SVN on the mac was a great tool for these users; or at least those on a mac...)

-David