can anyone give me a quick hand with namespaces and the UserFrosting environment?

To explain my issue, I'm using TCPDF to create a PDF document from data within UserFrosting. I've created a custom class, MyPDF, in the UserFrosting namespace so I can create a PDF within the UF namespace by typing `$pdf = new MyPDF(blahblah);` and that works fine.

The issue is with the MyPDF class itself - I need to be able to reference config vars from UF and don't know how I can do that - i.e.:

```
namespace UserFrosting;

 class MyPDF extends \TCPDF_TCPDF {

   public function Header() {
      $image_location = $this->_app->config('upload.path')

```

How can I access `config` from within `MyPDF`? :?:

I've tried:

```
class MyPDF extends \TCPDF_TCPDF {

 public function Header() {
    $ufapp = new UFModel();
    $image_location = $ufapp->config('upload.path')

```

... but no dice. I'm getting this error: 

```
Cannot instantiate abstract class UserFrosting\UFModel

```