Update Course.php

Changed the Mysql connection names because at first we used the local server and forgot to change the details when pushing to gitHub.

Course.php

@@ -144,7 +144,7 @@ if( $_SESSION['user_type'] == "Student")
     
  <?php
 // Connect to MySQL database
-$con = mysqli_connect("localhost","username","password","lrr");
+$con = mysqli_connect("localhost",  $mysql_username, $mysql_password, "lrr");
 
 // Check connection
 if (mysqli_connect_errno())