Moodle: enable DEBUG messages

Trabla: how to enable debug messages in Moodle 2.3.11

Solving:

1. Find config.php file in moodle root
2.  Put code there

// Force a debugging mode regardless the settings in the site administration
// @error_reporting(1023);  // NOT FOR PRODUCTION SERVERS!
@ini_set('display_errors', '1'); // NOT FOR PRODUCTION SERVERS!
$CFG->debug = 32767;         // DEBUG_DEVELOPER // NOT FOR PRODUCTION SERVERS!
// for Moodle 2.0 - 2.2, use:  $CFG->debug = 38911;  
$CFG->debugdisplay = true;   // NOT FOR PRODUCTION SERVERS!

Moodle Official Docs here -  http://docs.moodle.org/23/en/Debugging