Undefined property: Illuminate\Database\Eloquent\Relations\HasOne::$user_id

I'm just a beginner at laravel, Sorry if it's a stupid question

Here's my controller :-

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\User;
use App\Profile;
use Auth;



class ProfilesController extends Controller
{

  public function _construct()
  {
    $this->middleware('auth');
  }

  public function create()
  {
    return view('bio');
  }

  public function store(Request $request)
  {
  auth()->user()->profile()->user_id;
    // create Bio
    $profile = new Profile;

    $profile->bio = $request->input('bio');
    $profile->save();
    return redirect('/home');

  }


}

Here's My Model:-

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Profile extends Model
{
  protected $gaurded = [];
protected $fillable = ['user_id', 'bio'];

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

Here Are My Tables

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Profile extends Model
{
  protected $gaurded = [];
protected $fillable = ['user_id', 'bio'];

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

Here's My User Model:-

  public function profile()
    {
      return $this->hasOne(Profile::class);
    }

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

I'm getting this error "Undefined property: Illuminate\Database\Eloquent\Relations\HasOne::$user_id" I don't know where i went wrong please help me and guide me if u can Thanks