Adds variable additional_php_packages (#165)

* Allows to add additional_php_packages

Allows to add additional_php_packages as var. Extends php_packages to install.

* Adds description for variable additional_php_packages

Adds description of new variable for additional php packages.

README.md

@@ -18,6 +18,10 @@ A list of the PHP packages to install (OS-specific by default). You'll likely wa
 
 _Note: If you're using Debian/Ubuntu, you also need to install `libapache2-mod-fastcgi` (for cgi/PHP-FPM) or `libapache2-mod-php7.0` (or a similar package depending on PHP version) if you want to use `mod_php` with Apache._
 
+    additional_php_packages: []
+    
+A list of additional PHP packages to install without overriding the default.
+
     php_enable_webserver: true
 
 If your usage of PHP is tied to a web server (e.g. Apache or Nginx), leave this default value. If you are using PHP server-side or to run some small application, set this value to `false` so this role doesn't attempt to interact with a web server.

tasks/main.yml

@@ -8,6 +8,11 @@
     php_packages: "{{ __php_packages | list }}"
   when: php_packages is not defined
 
+- name: Define additional php_packages.
+  set_fact:
+    php_packages: "{{ php_packages | list + additional_php_packages | list }}"
+  when: additional_php_packages is defined
+
 - name: Define php_webserver_daemon.
   set_fact:
     php_webserver_daemon: "{{ __php_webserver_daemon }}"