How to save data in database safe in laravel 5.1?

I am new in Laravel , I want have a Comment Form and anybody can fill it , and the iput data will be inserted in database after a validating :

<?php

namespace App\Http\Controllers;

use App\comments;
use Illuminate\Http\Request;
use App\Http\Requests;
use App\Http\Controllers\Controller;

class CommentController  extends Controller
{
    public function postCommentNew( Request $request)
    {
        $this->validate($request, [
            'commenter' => 'required|max:255',
            'email' => 'required|max:255',
            'comment' => 'required',
            'post_id' => 'required'
        ]);
        comments::create( $request->all() );

        return redirect()->back()->with('success' , 'Comment Submited') ;
    }


}

now I want to be sure that nobody will not damage my site ! I want to save data completely safe ! I dont know is it necessary to sanitize form input ? if your answer is yes , How should I do it ?

I have seen this here :

public function sanitize()
    {
        $input = $this->all();

        if (preg_match("#https?://#", $input['url']) === 0) {
            $input['url'] = 'http://'.$input['url'];
        }

        $input['name'] = filter_var($input['name'], FILTER_SANITIZE_STRING);
        $input['description'] = filter_var($input['description'], 
        FILTER_SANITIZE_STRING);

        $this->replace($input);     
    }

via Chebli Mohamed