In a recent project, I needed to add a file which was in a folder that was ignored using the .gitignore file.
Now I could edit the .gitignore file, commit the file, then edit the .gitignore again. But this seemed like a cumbersome way to do it.
Luckily I found that the git-add command has a --force option.
-f --force Allow adding otherwise ignored files.
For example:
git add --force ignored-file.php
Enjoy.