Updated README

Author: jverdeyen

README.md

@@ -16,14 +16,35 @@ php:
 
 ## PHP version
 
-To use a specific PHP version, append the version number to the image name. 
+To use a specific PHP version, append the version number to the image name.
 
 Eg: `image: yappabe/php:5.6`
 
 The following PHP versions are available:
 
-* PHP 7.0.0 (jessie stable)
+* PHP 7.0 (jessie stable)
 * PHP 5.6 (jessie stable)
 * PHP 5.4 (wheezy stable)
 * PHP 5.3 (squeeze stable)
 
+## Configurations
+
+You can configure the following environment vars, these are the defaults.
+
+```
+ENV ENVIRONMENT dev
+ENV PHP_FPM_USER www-data
+ENV PHP_FPM_PORT 9000
+ENV PHP_ERROR_REPORTING "E_ALL \& ~E_NOTICE \& ~E_STRICT \& ~E_DEPRECATED"
+```
+
+## Development and permissions
+
+Run php-fpm process as `root` user to avoid cli and fpm permission collissions.
+Never ever use this in production!
+
+```
+ENV PHP_FPM_USER www-data
+```
+
+