L5.1 roles and permissions Call to undefined method hasRole()

I had follow the tutorial on laracast for roles and permissions. I have check the code form the tutorial and my code and there are no difference, but i get the error message: BadMethodCallException in Builder.php line 2071: Call to undefined method Illuminate\Database\Query\Builder::hasRole().

<?php

namespace App;

use Illuminate\Auth\Authenticatable;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Auth\Passwords\CanResetPassword;
use Illuminate\Foundation\Auth\Access\Authorizable;
use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;
use Illuminate\Contracts\Auth\Access\Authorizable as AuthorizableContract;
use Illuminate\Contracts\Auth\CanResetPassword as CanResetPasswordContract;

class User extends Model implements AuthenticatableContract,
                                    AuthorizableContract,
                                    CanResetPasswordContract
{
    use Authenticatable, Authorizable, CanResetPassword, HasRoles;

    protected $table = 'users';
    protected $fillable = ['name', 'email', 'password', 'user_name'];
    protected $hidden = ['password', 'remember_token'];

}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{
    /**
     * A role may be given various permissions.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function permissions()
    {
        return $this->belongsToMany(Permission::class);
    }

    /**
     * Grant the given permission to a role.
     *
     * @param  Permission $permission
     * @return mixed
     */
    public function givePermissionTo(Permission $permission)
    {
        return $this->permissions()->save($permission);
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Permission extends Model
{
    /**
     * A permission can be applied to roles.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }
}

<?php

namespace App;

trait HasRoles
{

    /**
     * A user may have multiple roles.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }

    /**
     * Assign the given role to the user.
     *
     * @param  string $role
     * @return mixed
     */
    public function assignRole($role)
    {
        return $this->roles()->save(
            Role::whereName($role)->firstOrFail()
        );
    }

    /**
     * Determine if the user has the given role.
     *
     * @param  mixed $role
     * @return boolean
     */
    public function hasRole($role)
    {
        if (is_string($role)) {
            return $this->roles->contains('name', $role);
        }

        return !! $role->intersect($this->roles)->count();
    }

    /**
     * Determine if the user may perform the given permission.
     *
     * @param  Permission $permission
     * @return boolean
     */
    public function hasPermission(Permission $permission)
    {
        return $this->hasRole($permission->roles);
    }
}

<?php

namespace App\Providers;
use App\Permission;
use Illuminate\Contracts\Auth\Access\Gate as GateContract;
use Illuminate\Foundation\Support\Providers\AuthServiceProvider as ServiceProvider;

class AuthServiceProvider extends ServiceProvider
{
    /**
     * The policy mappings for the application.
     *
     * @var array
     */
    protected $policies = [
        'App\Model' => 'App\Policies\ModelPolicy',
    ];

    /**
     * Register any application authentication / authorization services.
     *
     * @param  \Illuminate\Contracts\Auth\Access\Gate  $gate
     * @return void
     */
    public function boot(GateContract $gate){
        parent::registerPolicies($gate);
        
        // Dynamically register permissions with Laravel's Gate.
        foreach ($this->getPermissions() as $permission) {
            $gate->define($permission->name, function ($user) use ($permission) {
                return $user->hasPermission($permission);
            });
        }
    }
    protected function getPermissions()
    {
        return Permission::with('roles')->get();
    }

}

<?php
if(Auth::user()->hasRole('admin')){
            return 'JA';
        }
        return 'NEE';