.gitignore... ignored

[manaus]

I’m using Codekit, and added its config file to the .gitignore file.
Still, when I make a change to a file, there it is, among the modified files list, asking for Discard or Stage.
How do I force ignore of a file?

Thanks!

[manaus]

Ok hopefully solved, it was a cache issue.
I used this command:

git rm --cached config.codekit3