GIT: ignoring modified versioned files

There is rare case when team decides to put some of IDE-project related files into repo. But some of them may be modified by IDE or on personal basis and annoy developer on each commit. Here i found way to ignore files besides modifying .gitignore:

$ git update-index --assume-unchanged <path-to your files>

to undo it just do:

$ git update-index --no-assume-unchanged <path-to your files>

found here -> https://help.github.com/articles/ignoring-files#ignoring-versioned-files
doc reference here -> http://git-scm.com/docs/git-update-index.html