title: Syntax error or access violation: 1067 Invalid default value for 'created_at'
body: <p>I install laravel 5.5 and When I run <code>php artisan migrate</code> show me this error</p>
  
  <blockquote>
    <p>[Illuminate\Database\QueryException]
      SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes (SQ
      L: alter table <code>users</code> add unique <code>users_email_unique</code>(<code>email</code>))  </p>
  </blockquote>
  
  <p>And I add below code on <code>AppServiceProvider.php</code></p>
  
  <pre><code> public function boot()
  {
       Schema::defaultStringLength(191); //Solved by increasing StringLength
  }
  </code></pre>
  
  <p>And then show me this error</p>
  
  <blockquote>
    <p>[Illuminate\Database\QueryException]
      SQLSTATE[42000]: Syntax error or access violation: 1067 Invalid default value for 'created_at' (SQL: create table <code>
      password_resets</code> (<code>email</code> varchar(191) not null, <code>token</code> varchar(191) not null, <code>created_at</code> timestamp not null) de
      fault character set utf8mb4 collate utf8mb4_unicode_ci)</p>
  </blockquote>