Added support for $_SERVER['CI_ENV'] in index.php
Remember this is entirely optional, nothing will change if you do not which to use Multiple Environments just like right now. If you DO set CI_ENV you can manipulate the switch that controls error reporting, etc, so set it to "production" on your live site to hide errors from users. If you don't require this logic you can remove it, or change it entirely to check HTTP_HOST for environment subdomains, or check IP address, etc.
diff --git a/index.php b/index.php
index 5a11901..3b00dd3 100644
--- a/index.php
+++ b/index.php
@@ -42,7 +42,7 @@
  *
  * NOTE: If you change these, also change the error_reporting() code below
  */
-	define('ENVIRONMENT', 'development');
+	define('ENVIRONMENT', isset($_SERVER['CI_ENV']) ? $_SERVER['CI_ENV'] : 'development');
 /*
  *---------------------------------------------------------------
  * ERROR REPORTING