cakephp，安装失败，太难安装了！

安装了好多次，一直提示失败。怎么安装啊！
root@ubuntu-virtual-machine:/var/www/html# php composer.phar create-project --prefer-dist cakephp/app huu
Installing cakephp/app (3.1.1)
- Installing cakephp/app (3.1.1)
Loading from cache
Created project in huu
Loading composer repositories with package information
Installing dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- cakephp/cakephp 3.2.x-dev requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.1.0-beta2 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.1.0-beta requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.1.0-RC1 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- cakephp/cakephp 3.1.0 requires ext-intl * -> the requested PHP extension intl is missing from your system.
- Installation request for cakephp/cakephp ~3.1 -> satisfiable by cakephp/cakephp[3.1.0, 3.1.0-RC1, 3.1.0-beta, 3.1.0-beta2, 3.2.x-dev].