require command adds new packages to the
composer.json file. A
composer.json file will be created if one doesn’t exist.
After adding/changing the requirements, the modified requirements will be installed or updated.
--update-with-dependencies (-w): Also update dependencies of the newly required packages, except those that are root requirements.
--update-with-all-dependencies (-W): Also update dependencies of the newly required packages, including those that are root requirements.
Circumvent php memory limit
php -d memory_limit=-1 composer.phar install