PHP7 : install ext-dom issue

I'm running laravel 5.4 on Ubuntu 16.04 server with PHP7. trying to install `cviebrock/eloquent-sluggable` package throw some error: pish@let:/home/sherk/ftp/www$ sudo composer require cviebrock/eloquent-sluggable Do not run Composer as root/super user! See https://getcomposer.org/root for details Using version ^4.2 for cviebrock/eloquent-sluggable ./composer.json has been updated Loading composer repositories with package information Updating dependencies (including require-dev) Your requirements could not be resolved to an installable set of packages. Problem 1 - phpunit/php-code-coverage 4.0.7 requires ext-dom * -> the requested PHP extension dom is missing from your system. - phpunit/php-code-coverage 4.0.7 requires ext-dom * -> the requested PHP extension dom is missing from your system. - Installation request for phpunit/php-code-coverage (installed at 4.0.7) -> satisfiable by phpunit/php-code-coverage[4.0.7]. To enable extensions, verify that they are enabled in those .ini files: - /etc/php/7.0/cli/php.ini - /etc/php/7.0/cli/conf.d/10-mysqlnd.ini - /etc/php/7.0/cli/conf.d/10-opcache.ini - /etc/php/7.0/cli/conf.d/10-pdo.ini - /etc/php/7.0/cli/conf.d/20-calendar.ini - /etc/php/7.0/cli/conf.d/20-ctype.ini - /etc/php/7.0/cli/conf.d/20-exif.ini - /etc/php/7.0/cli/conf.d/20-fileinfo.ini - /etc/php/7.0/cli/conf.d/20-ftp.ini - /etc/php/7.0/cli/conf.d/20-gd.ini - /etc/php/7.0/cli/conf.d/20-gettext.ini - /etc/php/7.0/cli/conf.d/20-iconv.ini - /etc/php/7.0/cli/conf.d/20-json.ini - /etc/php/7.0/cli/conf.d/20-mbstring.ini - /etc/php/7.0/cli/conf.d/20-mcrypt.ini - /etc/php/7.0/cli/conf.d/20-mysqli.ini - /etc/php/7.0/cli/conf.d/20-pdo_mysql.ini - /etc/php/7.0/cli/conf.d/20-phar.ini - /etc/php/7.0/cli/conf.d/20-posix.ini - /etc/php/7.0/cli/conf.d/20-readline.ini - /etc/php/7.0/cli/conf.d/20-shmop.ini - /etc/php/7.0/cli/conf.d/20-sockets.ini - /etc/php/7.0/cli/conf.d/20-sysvmsg.ini - /etc/php/7.0/cli/conf.d/20-sysvsem.ini - /etc/php/7.0/cli/conf.d/20-sysvshm.ini - /etc/php/7.0/cli/conf.d/20-tokenizer.ini You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode. Installation failed, reverting ./composer.json to its original content. I have no problem installing this package on local version of the app .