I am building static websites with Middleman. I am finding that clients want the ability to update the site's content.
I am wondering if there is a workable solution that would allow a client to update a Middleman site without them having to edit the source code.
Have you looked at Prose?
It's built for Jekyll sites, but you can edit any Markdown file in a GitHub repo and it will have a nice little editor. I've heard you can make the GUI editing for the frontmatter work if you mess around with the prose.yml, documented here: https://github.com/prose/prose/wiki/Prose-Configuration
I'm looking to do a similar thing and this is the best thing we've been able to come up with so far.