public function insert(){
        $rules = array(
            'code' => 'required',
            'name' => 'required',
            'category_id' => 'required|numeric',
            'price' => 'numeric',
            'sock_qty' => 'numeric'
        );
        $messages = array(
            'required' => 'กรุณากรอกข้อมูล Attribute ให้ครบถ้วน',
            'numeric' => 'กรุณากรอกข้อมูล Attribute ให้เป็นตัวเลข'
        );
        $validator = Validator::make(Input::all(),$rules,$messages);
        if($validator->fails()){
            return redirect('product/add/')->withErrors($validator)->withInput();
        }
        $product->code = Input::get('code');
        $product->name = Input::get('name');
        $product->category_id = Input::get('category_id');
        $product->price = Input::get('price');
        $product->stock_qty = Input::get('stock_qty');
        if(Input::hasFile('image')){
            $f = Input::file('image');
            $upload_to = 'upload/images';
            //get path
            $relative_path = $upload_to.'/'.$f->getClientOriginalName();
            $absolute_path = public_path().'/'.$upload_to;
            //upload file
            $f->move($absolute_path,$f->getClientOriginalName());
            //save image to database
            $product->image_url = $relative_path;
            //$product->save();
            Image::make(public_path().'/'.$relative_path)->resize(250,250)->save();
            $product->save();
        }
        return redirect('product')->with('ok',true)->with('msg','บันทึก');
    }