Revert "Update index.php"

This reverts commit bb1ad0d875.

index.php

@@ -54,7 +54,7 @@
  * NOTE: If you change these, also change the error_reporting() code below
  */
 	#define('ENVIRONMENT', isset($_SERVER['CI_ENV']) ? $_SERVER['CI_ENV'] : 'development');
-	define('ENVIRONMENT', 'production');
+	define('ENVIRONMENT', 'development');
 
 /*
  *---------------------------------------------------------------