How to ignore local changes to configuration files in git

When developing a project you need to be able to run it in order to test it. But you don't want local changes to the configuration files to be committed. Most 'solutions' to this problem suggest untracking (removing) it from the repository. But if you want to keep the file in your project, then use:

git update-index --skip-worktree filenameOrPath

This keeps the file in the respository, but lets you change your local copy freely without including changes in commits.