http://blog.pagebakers.nl/2009/01/29/git-ignoring-changes-in-tracked-files/
git update-index --assume-unchanged <file>
If you wanna start tracking changes again run the following command:
git update-index --no-assume-unchanged <file>
list
git ls-files -v
H .gitignore
H pgbouncer.ini
h pgbouncer_local.ini
H run_pgbouncer
H users.txt