Usage:
1. Create a configuration file using the template action:
yii asset/template /path/to/myapp/config.php
2. Edit the created config file, adjusting it for your web application needs.
3. Run the 'compress' action, using created config:
yii asset /path/to/myapp/config.php /path/to/myapp/config/assets_compressed.php
4. Adjust your web application config to use compressed assets.
Note: in the console environment some path aliases like @webroot and @web may not exist,
so corresponding paths inside the configuration should be specified directly.
Note: by default this command relies on an external tools to perform actual files compression,
check [[jsCompressor]] and [[cssCompressor]] for more details.