I have a Vagrant running Linux and I\'m trying to install Symfony.
After the command composer create-project symfony/framework-standard-edition ./ \"2.5.*\"
composer create-project symfony/framework-standard-edition ./ \"2.5.*\"
Just run
sudo chmod -R 777 /folder/path
This will give you write access to the folder you are running composer in. I know this is an old post but this works so I have to share it.