.gitignore rules are not updated automatically

[vegaminer]

Local changes to .gitignore are not taking into account until next checkout or unmount/mount

How to reproduce:

1. cd /var/www/repo_root/current/
2. vi /var/www/repo_root/current/.gitignore, add my_tmp_dir/
3. echo foo > my_tmp_dir/boo.txt
4. boo.txt is added and pushed to repo