Using Git to files outside the repo
I decided that I wanted to keep a few files in my home directory in version control (.vimrc, .bashrc, .config/awesome), but don't like making that directory a git repo because then the shell prompts always say I'm in a branch. To fix this, I init'd a repo in my normal place then ran:
git config --local --add core.worktree $HOME
And now I can add things like "git add ~/.bashrc" without having to keep that repo in my home directory.