Fix typo

web/includes/Monitor.php

@@ -400,7 +400,7 @@ Logger::Debug("sending command to $url");
       if ( array_key_exists('Id', $this) and $this->{'Id'} ) {
         $this->{'GroupIds'} = dbFetchAll( 'SELECT GroupId FROM Groups_Monitors WHERE MonitorId=?', 'GroupId', array($this->{'Id'}) );
       } else {
-        $this0->{'GroupIds'} = array();
+        $this->{'GroupIds'} = array();
       }
     }
     return $this->{'GroupIds'};