Add global composer installation and running 'composer install'

ansible/playbook.yml

@@ -9,3 +9,4 @@
     - php
     - xdebug
     - app
+    - composer

ansible/roles/composer/tasks/main.yml

@@ -0,0 +1,5 @@
+- name: Install Composer
+  shell: curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer creates=/usr/local/bin/composer
+
+- name: Install packages
+  shell: cd /vagrant && composer install --optimize-autoloader