php - how to remove the error showing below:(laravel framework) -

i have viewed lot off documents already. trying login, not working. showing errors. don't know reason.i new in laravel

this controller code

    public function do_login()     {         $credentials = [         'username'=>input::get('username'),         'password'=>input::get('password')     ];      $rules = [         'username' => 'required',         'password'=>'required'     ];      //validating credentials.     $validator = validator::make($credentials,$rules);      //in case credentials valid. try login user.     if($validator->passes())     {         if (auth::attempt($credentials))         {             //if successfull redirect user              return redirect::to('home');         }         else         {             //else send login failure message.             return redirect::back()->withinput()->with('failure','username or password invalid!');         }      }     else     {         //send validation errors.          return redirect::back()->witherrors($validator)->withinput();     }  }       

this model code:

    <?php namespace laravel\laravel_1st_project\models\usermodel;      use illuminate\auth\userinterface;     use illuminate\auth\reminders\remindableinterface;      class usermodel extends \eloquent implements userinterface , remindableinterface     {         public $table = "user";         protected $primarykey = 'employee_id';          //public $timestamps = false;     } 

this app\config\auth.php :

  'model' => 'laravel\laravel_1st_project\usermodel',       'table' => 'user',  'reminder' => array(      'email' => 'email.auth.reminder',      'table' => 'password_reminders',      'expire' => 60,  ), 

error :