added constants.php file and implemented constants for file system modes
diff --git a/system/application/config/constants.php b/system/application/config/constants.php
new file mode 100644
index 0000000..ace3f8b
--- /dev/null
+++ b/system/application/config/constants.php
@@ -0,0 +1,21 @@
+<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
+
+/*
+|--------------------------------------------------------------------------
+| File and Directory Modes
+|--------------------------------------------------------------------------
+|
+| These prefs are used when checking and setting modes when working
+| with the file system. The defaults are fine on servers with proper
+| security, but you may wish (or even need) to change the values in
+| certain environments (Apache running a separate process for each
+| user, PHP under CGI with Apache suEXEC, etc.). Octal values should
+| always be used to set the mode correctly.
+|
+*/
+define('FILE_READ_MODE', 0644);
+define('FILE_WRITE_MODE', 0666);
+define('DIR_READ_MODE', 0755);
+define('DIR_WRITE_MODE', 0777);
+
+?>
\ No newline at end of file