Add optional DB_PREFIX configuration option

Author: iloveitaly

config/application.php

@@ -35,7 +35,7 @@
  */
 define('DB_CHARSET', 'utf8');
 define('DB_COLLATE', '');
-$table_prefix = 'wp_';
+$table_prefix = getenv('DB_PREFIX') ? getenv('DB_PREFIX') : 'wp_';
 
 /**
  * WordPress Localized Language