assets/              contains application assets such as JavaScript and CSS
protected
    assets/              contains application assets such as JavaScript and CSS
    command/             contains console command classes
    config/              contains app configurations
    controllers/         contains Web controller classes
    models/              contains app-specific model classes
    runtime/             contains files generated during runtime
    views/               contains view files for the Web application
    web/                 contains the entry script and Web resources
    widgets/             contains app widgets
vendor/                  contains dependent 3rd-party packages
environments/            contains environment-based overrides

$ git clone https://github.com/yii-id/yii2-playground.git playground
$ cd playground
$ composer install --prefer-dist
$ php init
$ php yii migrate