globalでgitignoreしたい場合
Git - gitignore Documentation
Patterns which a user wants Git to ignore in all situations (e.g., backup or temporary files generated by the user’s editor of choice) generally go into a file specified by core.excludesFile in the user’s ~/.gitconfig. Its default value is $XDG_CONFIG_HOME/git/ignore. If $XDG_CONFIG_HOME is either not set or empty, $HOME/.config/git/ignore is used instead
ということなので$HOME/.config/git/ignoreを作成してそこにgitに含めたくないファイルを追加すればok。
git