Cannot gitignore codeception.yml file in Laravel 5?

I am working with codeception in Laravel 5 and I have a codeception.yml file sitting in my base project directory which I want to ignore because it has database credentials which vary across machines.

.gitignore file:

/.phpstorm.meta.php
/_ide_helper.php
/vendor
/node_modules
Homestead.yaml
Homestead.json
.env
.env.testing
codeception.yml

I thought this should do it. But git is still tracking the file. What am I doing wrong?

via Chebli Mohamed