We keep a lot of Storm documentation in the main repository, which we use to generate release specific docs on https://github.com/apache/storm-site. This is fine and works well.
We also have a bunch of files that are not release specific, e.g. /docs/_includes or /docs/_layout. The process we describe for building the site doesn't copy these files from the main repository, and it looks like the files in storm-site are newer than the ones in the main repo.
I don't think there's any point to having these files in the main repo. They're not release specific, so we can just keep a single copy in the storm-site repo.