Comment.php

<?php

namespace App;

class Comment extends Model
{
    public function post()
    {
        return $this->belongsTo(Post::class);
    }

    public function user()
    {
        return $this->belongsTo(User::class);
    }
}

CommentsController.php

<?php

namespace App\Http\Controllers;

use App\Post;

class CommentsController extends Controller
{
    public function store(Post $post)
    {
        $this->validate(request(), ['body' => 'required|min:2']);

        $post->addComment(request('body'));

        return back();
    }
}

Model.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model as Eloquent;

class Model extends Eloquent
{
    protected $guarded = [];
}

Post.php

<?php

namespace App;

class Post extends Model
{
    public function comments()
    {
        return $this->hasMany(Comment::class);
    }

    public function user()
    {
        return $this->belongsTo(User::class);
    }

    public function addComment($body)
    {
        // dd($this->comments());
        $this->comments()->create(compact('body'));
    }
}

PostsController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Post;

class PostsController extends Controller
{
    public function __construct()
    {
        $this->middleware('auth')->except(['index', 'show']);
    }

    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
        $posts = Post::latest()->get();

        return view('posts.index', compact('posts'));
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create()
    {
        return view('posts.create');
    }

    /**
     * Store a newly created resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function store(Request $request)
    {
        $this->validate(request(),[
            'title' => 'required',
            'body' => 'required'
        ]);

        auth()->user()->publish(new Post(request(['title', 'body'])));

        return redirect('/posts');
    }

    /**
     * Display the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function show(Post $post)
    {
        return view('posts.show', compact('post'));
    }

    /**
     * Show the form for editing the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function edit($post)
    {
        //
    }

    /**
     * Update the specified resource in storage.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function update(Request $request, $post)
    {
        //
    }

    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function destroy($post)
    {
        //
    }
}

User.php

<?php

namespace App;

use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    public function posts()
    {
        return $this->hasMany(Post::class);
    }

    public function publish(Post $post)
    {
        $this->posts()->save($post);
    }
}