安装 composer 和 drush

php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
php composer-setup.php --install-dir=/usr/local/bin --filename=composer --version=1.6.3
rm composer-setup.php
git clone  https://github.com/drush-ops/drush.git .drush
cd .drush/
git checkout 7.4.0
composer install -vvv
ln -s /root/.drush/drush /usr/local/bin/