Codeigniter Bild hochladen und den Pfad zur Datenbank

Bin ich ein bisschen ein problem versucht zu machen, ein upload-Formular in codeigniter.
Nicht sicher, was ich falsch mache, alles andere ist immer korrekt in der Datenbank. Ich schaute in den Unterlagen und versuchte mehrere Dinge, aber ich bin nicht immer weiter.. Jedes feedback ist sehr willkommen!

Vielen Dank im Voraus.

Modell:

public function set_newstudent()
    {
        $this->load->helper('url');

        $slug = url_title($this->input->post('naam'), 'dash', TRUE);

                 $config['upload_path'] = '/file_path/';
                 $config['allowed_types'] = 'gif|jpg|png|jpeg';
                 $this->load->library('upload', $config);
                 $this->upload->data('full_path'););
                 $data_upload_files = $this->upload->data();

                 $image = $data_upload_files[full_path];

                 $data = array(

            'naam' => $this->input->post('naam'),
            'voornaam' => $this->input->post('voornaam'),
            'id' => $slug,
            'text' => $this->input->post('text'),
            'picture'=>$this->input->post('picture')
    );

        return $this->db->insert('student', $data);
    }

controller:

public function create()
            {
                $this->load->helper('form');
                $this->load->library('form_validation');

                $data['title'] = 'Create a new Student';

                $this->form_validation->set_rules('naam', 'Naam', 'required');
                $this->form_validation->set_rules('voornaam', 'Voornaam', 'required');
                $this->form_validation->set_rules('text', 'Text', 'required');

                if ($this->form_validation->run() === FALSE)
                    {
                    $this->load->view('templates/header', $data);
                    $this->load->view('students/create');
                    $this->load->view('templates/footer');

                    }
                else
                    {
                    $this->student_model->set_newstudent();
                    $this->load->view('students/success');
                    }
            }

anzeigen:

<?php echo validation_errors(); ?>


<?php echo form_open_multipart('student/create');?>

<div class="form-group">
<label for="naam">Naam</label><br>
<input type="input" name="naam" class="form-control" /><br />
</div>
<div class="form-group">
<label for="voornaam">Voornaam</label><br>
<input type="input" name="voornaam" class="form-control"/><br />
</div>
<div class="form-group">
<label for="text">Vertel iets over jezelf:</label><br>
<textarea name="text" class="form-control" rows="5"></textarea><br />
</div>

<div class="form-group">
<label for="text">Kies een profiel foto:</label><br>
<input type="file" name="userfile"  class="btn btn-default btn-file" />

</div>
<input type="submit" class="btn btn-success" name="submit" 
value="Create student" style="width:100%;margin-bottom:1%" />

</form>