Git from your vendor directory with PHPStorm and Github
PHPStorm allows to make changes to Composer vendor repositories by using multiple repositories in a project. When the vendor repository is on Bitbucket, this works out of the box. When it is on Github, a push will fail. To solve this you need to set the Github protocol to https:
php composer.phar config --global github-protocols https
After that, your repository needs to be updated. For example: remove it from your vendor directory and run a composer update.