Ignore changes to GIT committed file.

Suppose you have some config.yaml that was committed in GIT with some default data. You can use config-dev.yaml or you can change the original one. But each change will be tracked in git of course. You can make GIT think this file is not changed:

git update-index --assume-unchanged <file>

But if you want to keep tracked of new changes you can resume tracking changes:

git update-index --no-assume-unchanged <file>