Consider using subtrees?

[kangwonlee]

• may need to git merge -Xsubtree=<folder> … --allow-unrelated-histories
• Github says
  git pull -s subtree remotename branchname
• Also, pushing commits from the top level to the subtree repository seems to create duplicate commits
  git push <subtree repo>git subtree split --prefix= :<subtree repo branch>
• Then it seems more reasonable to work within a subtree, push to subtree remote, and git pull -s subtree ...

[kangwonlee]

• When introducing subtrees, consider adding automation scripts

[kangwonlee]

• It seems better to keep track of the whole repository than subsections.