Making my data movable ⇒

Now that I have my blog posts stored in Markdown, I need to automate backup of those posts so that I always have a current copy. I am hoping to find an existing plugin/service that does this but so far I haven't found anything perfect. IFTTT almost does it but it won't find my WP installation properly. There are also several WP backup plugins that back up to Dropbox but that won't work either. So I either have to write my own WP plugin (which I don't want to do) or find a plugin that does it.