Este es mi código, mi foto no se puede insertar en la base de datos.

En realidad quiero hacer un examen en línea con el codeigniter. Quiero subir la pregunta con la foto. pero cuando intenté subir la imagen, el código no funciona.

pero la pregunta éxito se inserta en la base de datos. solo la imagen no se pudo cargar

Controlador:

function insert(){
		$nama_asli = $_FILES['userfile']['name'];
		$config ['file_name'] = $nama_asli;
		$config ['upload_path'] = './images';
		$config ['allowed_types'] = 'gif|jpg|png|jpeg';
		$config ['max_size'] = '2500';
			
		$this->load->library('upload', $config);
			
		$upload_data = $this->upload->data();
		$file_name = $upload_data['file_name'];	
		
		$id_soal = '';
		$soal = $_POST['soal'];
		$a = $_POST['a'];
		$b = $_POST['b'];
		$c = $_POST['c'];
		$d = $_POST['d'];
		$kunci = $_POST['kunci'];
		$status = $_POST['status'];

		$data = array(
			'id_soal' => $id_soal,
			'soal' => $soal,
			'a' => $a,
			'b' => $b,
			'c' => $c,
			'd' => $d,
			'kunci' => $kunci,
			'status' => $status,
			'foto' => $file_name,
			);

		$hasil = $this->soal_model->Simpan('soal', $data);

		if($hasil>=1){
			redirect('dashboard/index', $data);
		}
	}

Modelo:

class Soal_model extends Ci_Model {

  public function Ambil($where= "") {
    $data = $this->db->query('select * from soal '.$where);
    return $data;
  }
  
  public function Simpan($tabel, $data){
    $res = $this->db->insert($tabel, $data);
    return $res;
  }

Ver:

<form role="form" action="<?php echo base_url(); ?>dashboard/insert" method="POST" enctype="multipart/form-data">
<form class="form-horizontal" method="post" style = "margin : 10px;">
		<div class = "row">
		<div class = "col-sm-offset-3 col-sm-6">
		<div class="form-group">
		<label>Soal :</label>
		<textarea type="text" class="form-control" name="soal" id="soal" required></textarea>
		</div>
		
		<div class="form-group">
		<label>Jawaban A :</label>
		<input type="text" class="form-control" 
		placeholder="Type Here" name="a" id="a" required/>
		</div>
		
		<div class="form-group">
		<label>Jawaban B :</label>
		<input type="text" class="form-control" 
		placeholder="Type Here" name="b" id="b" required/>
		</div>
		
		<div class="form-group">
		<label>Jawaban C :</label>
		<input type="text" class="form-control" 
		placeholder="Type Here" name="c" id="c" required/>
		</div>
		
		<div class="form-group">
		<label>Jawaban D :</label>
		<input type="text" class="form-control" 
		placeholder="Type Here" name="d" id="d" required/>
		</div>
		
		<div class="form-group">	
		<label>Kunci :</label>
		<select name="kunci" id="kunci" class="form-control">
		<option>Select</option> 
		<option>A</option>  
		<option>B</option> 
		<option>C</option>
		<option>D</option>
		</select> 
		</div>
		
		<div class="form-group">	
		<label>Status :</label>
		<select name="status" id="status" class="form-control">
		<option value="">Select</option> 
		<option value="tampil">Tampil</option>  
		<option value="tidak">Tidak</option> 
		</select> 
		
		<div class="form-group">	
		<label>Photo :</label>
		<input type="file" name="foto" id="foto" size="20"/>
		</div>
		<br>
		
		<div class="form-group">	
        <button type="submit" class="btn btn-default">Simpan</button>
		<button type="reset" class="btn btn-default">Hapus</button>
		</div>
		</div>
		</div>
	</form>
	

Base de datos: