我怎样才能在github中推送这个修改过的文件
% git status
# On branch master
# Changed but not updated:
# (use "git add <file>..." to update what will be committed)
# (use "git checkout -- <file>..." to discard changes in working
# directory)
# modified: login.php
no changes added to commit (use "git add" and/or "git commit -a")