Add index.php

index.php

 <?php echo "Natnicha Wettamma";
+$servername = "db";
+$username = "demo";
+$password = "12456";
+
+// Create connection
+$conn = new mysqli($servername, $username, $password);
+
+// Check connection
+if ($conn->connect_error) {
+  die("Connection failed: " . $conn->connect_error);
+}
+echo "Connected successfully";
 ?>