moell-blog/app/Http/Controllers/TagController.php

<?php

namespace App\Http\Controllers;

use App\Models\Tag;
use Illuminate\Http\Request;

use App\Http\Requests;
use App\Repositories\TagRepositoryEloquent;

class TagController extends Controller
{
    protected $tag;

    public function  __construct(TagRepositoryEloquent $tag)
    {
        $this->tag  = $tag;
    }

    public function index($id)
    {
        $tag = $this->tag->find($id);
        $articles = $tag->article()
            ->orderBy('sort','desc')
            ->orderBy('id', 'desc')
            ->paginate(15);
        return view('default.tag_article', compact('articles', 'tag'));
    }
}