Laravel nie mozna zapisac komentarza dla danego Posta

  public function create($post_id)
    {
        $post = Post::all()->find($post_id);
        return view('comments.create')->with('post',$post);
    }

    public function store(CreateCommentRequest $request)
    {
        $data = $request->all();
        $comment = new Comment($data);
        Auth::user()->comment()->save($comment);
        return redirect('/blog');
    } 

@extends('base')

@section('pageContent')
    <div class="row">
        <div class="col-md-8 col-md-offset-2">
            <div class="card">
                <div class="panel-body">
                    <!-- Formularz -->
                    @if(count($errors)>0)
                        <div class="alert alert-danger">
                            <ul>
                                @foreach($errors->all() as $error)
                                    <li>{{$error}}</li>
                                @endforeach
                            </ul>
                        </div>
                    @endif

                    {!! Form::open(['url'=>"/blog/add_comment/$post->id", 'class'=>'form-horizontal']) !!}
                    <div class="jumbotron">


                        <div class="form-group">
                            <div class="col-md-4 control-label">
                                {!! Form::label('content','Zawartosc: ') !!}
                            </div>

                            <div class="col-md-6">
                                {!! Form::textarea('content', null,['class'=>'form-control']) !!}
                            </div>
                        </div>


                        <div class="form-group">

                            <div class="col-md-6 col-md-offset-4">
                                {!! Form::submit('Zapisz',['class'=>'btn btn-primary']) !!}
                            </div>
                        </div>

                        <div class="form-group">
                            {{ Form::hidden('post_id',$post->id) }}
                        </div>

                    {!! Form::close() !!}
                </div>
            </div>
        </div>
    </div>
@endsection 

Route::get('/blog/add_comment/{id}', 'CommentsController@create');
Route::post('/blog/add_comment/{id}', 'CommentsController@store');
Route::get('/blog/deleteComment/{id}', 'CommentsController@deleteComment');

protected $fillable = [
        'favicon',
    ];