herokuでpostgreSQLのテーブルにinsertするとcolumn "UPDATED_AT" of relation "user" does not exist　・・・と帰ってくる

laravelでgithub認証をし、認証が通ったユーザをuserテーブルにinsertしようとすると、ローカルではエラーなく、意図通りの動きになるのですが、
Herokuでやると何故か表題に記載のエラーが発生し、データ書き込み時に項目が存在しないというエラーが返ってきます。

期待している動き

ローカルと同じく、問題なくユーザが追加し、リダイレクト先の画面が正常に表示される。

エラーメッセージ詳細

SQLSTATE[42703]: Undefined column: 7 ERROR: column "UPDATED_AT" of relation "user" does not exist LINE 1: insert into public.user (github_id, "created_at", "UPDATED_A... ^ (SQL: insert into public.user (github_id, "created_at", "UPDATED_AT") values (moriokameda,20/06/21 16:16:31,20/06/21 16:16:31))

試したこと

・insert文の項目名を全て大文字にしてみる。
・insert文の該当の項目名に""を入れる。
・insert文の該当の項目名を削除してみる

herokuの設定

DB_HOST
DB_CONNECTION
DB_PORT
DB_DATABASE
DB_USER
DB_PASSWORD
GITHUB_CLIENT_ID
GITHUB_CLIENT_SECRET
GITHUB_REDIRECT
APP_KEY

ソースコード

LoginController.php

 <?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\AuthenticatesUsers;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Socialite;

class LoginController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Login Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles authenticating users for the application and
    | redirecting them to your home screen. The controller uses a trait
    | to conveniently provide its functionality to your applications.
    |
    */

    use AuthenticatesUsers;

    /**
     * Where to redirect users after login.
     *
     * @var string
     */
    protected $redirectTo = '/home';

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware('guest')->except('logout');
    }

    /**
     * githubの認証ページへリダイレクト
     */
    public function redirectToProvider() {
        return Socialite::driver('github')->scopes(['read:user', 'public_repo'])->redirect();
    }

    /**
     * githubからユーザ情報を取得
     *
     * @return \Illuminate\Http\Response
     */
    public function handleProviderCallback(Request $request) {

        $github_user = Socialite::driver('github')->stateless()->user();
        $now = date('y/m/d H:i:s');
        $app_user = DB::select('select * from public.user where github_id = ?', [$github_user->user['login']]);

        if (empty($app_user)) {
            # code...
            DB::insert('insert into public.user (github_id,created_at,updated_at) values (?,?,?)', [$github_user->user['login'], $now, $now]);
        }

        $request->session()->put('github_token', $github_user->token);
        return redirect('github');
    }
}

GithubController.php

<?php
namespace App\Http\Controllers\Github;

use App\Http\Controllers\Controller;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Socialite;

class GithubController extends Controller
{
  public function top(Request $request) {
    $token = $request->session()->get('github_token', null);

    try {
      $github_user = Socialite::driver('github')->userFromToken($token);
    } catch (\Exception $e) {
      //throw $th;
      return redirect('login/github');
    }

    $client = new \GuzzleHttp\Client();
    $res = $client->request('GET', 'https://api.github.com/user/repos', [
      'auth' => [$github_user->user['login'], $token],
    ]);

    $app_user = DB::select('select * from public.user where github_id = ?', [$github_user->user['login']]);

    return view('github', [
      'user' => $app_user[0],
      'nickname' => $github_user->nickname,
      'token' => $token,
      'repos' => array_map(function ($o) {
        return $o->name;
      }, json_decode($res->getBody())),
    ]);
  }

  public function createIssue(Request $request) {
    $token = $request->session()->get('github_token', null);
    $user = Socialite::driver('github')->userFromToken($token);

    $client = new \GuzzleHttp\Client();
    $res = $client->request('POST', 'https://api.github.com/repos/' . $user->user['login'] . '/' . $request->input('repo') . '/issues', [
      'auth' => [$user->user['login'], $token],
      'json' => [
        'title' => $request->input('title'),
        'body' => $request->input('body'),
      ]
    ]);

    return view('done', [
      'response' => json_decode($res->getBody())->html_url
    ]);
  }
}

web.php

<?php

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/

Route::get('/', function () {
    return view('welcome');
});
Route::get('/user', "UserController@index");

// 掲示板
Route::get('/bbs', 'BbsController@index');
Route::post('/bbs', 'BbsController@create');

// github_login
Route::get('github', 'Github\GithubController@top');
Route::post('github/issue', 'Github\GithubController@createIssue');
Route::get('login/github', 'Auth\LoginController@redirectToProvider');
Route::get('login/github/callback', 'Auth\LoginController@handleProviderCallback');
Route::post('user', 'User\UserController@updateUser');

Route::get('/test', "TestController@index");

// Photo
Route::get('/home', 'HomeController@index');
Route::post('/upload', 'HomeController@upload');

service.php

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Third Party Services
    |--------------------------------------------------------------------------
    |
    | This file is for storing the credentials for third party services such
    | as Mailgun, SparkPost and others. This file provides a sane default
    | location for this type of information, allowing packages to have
    | a conventional file to locate the various service credentials.
    |
    */
    'github' => [
        'client_id' => env('GITHUB_CLIENT_ID'),
        'client_secret' =>env('GITHUB_CLIENT_SECRET'),
        // 'redirect' => '/login/github/callback',
        'redirect' => env('GITHUB_REDIRECT'),
    ],

    'mailgun' => [
        'domain' => env('MAILGUN_DOMAIN'),
        'secret' => env('MAILGUN_SECRET'),
        'endpoint' => env('MAILGUN_ENDPOINT', 'api.mailgun.net'),
    ],

    'postmark' => [
        'token' => env('POSTMARK_TOKEN'),
    ],

    'ses' => [
        'key' => env('AWS_ACCESS_KEY_ID'),
        'secret' => env('AWS_SECRET_ACCESS_KEY'),
        'region' => env('AWS_DEFAULT_REGION', 'us-east-1'),
    ],

    'sparkpost' => [
        'secret' => env('SPARKPOST_SECRET'),
    ],

];

2020_06_18_120744_create-table.php

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        //
        Schema::create('user', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name')->nullable();
            $table->string('comment')->nullable();
            $table->string('github_id');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        //
        Schema::drop('user');
    }
}