title: Migration error on timestamp change field
body: <p>In laravel 5.7/mysql 5 app I want to set default value to timestamp field(it was not set on creation):</p>
  
  <pre><code>   $table-&gt;timestamp('created_at')-&gt;useCurrent()-&gt;change();
  </code></pre>
  
  <p>But I got error :</p>
  
  <pre><code> Unknown column type "timestamp" requested. Any Doctrine type that you use has to be registered with \Doctrine\DBAL\Types\Type::addType(). You can get a list of all the known types with \Doctrine\DBAL\Types\Type::getTypesMap(). If this error occurs during database introspection then you might have forgotten to register all database types for a Doctrine Type. Use AbstractPlatform#registerDoctrineTypeMapping() or have your custom types implement Type#getMappedDatabaseTypes(). If the type name is empty you might have a problem with the cache or forgot some mapping information.
  
    at /mnt/_work_sdb8/wwwroot/lar/BoxBooking2/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php:267
      263|      * @return \Doctrine\DBAL\DBALException
      264|      */
      265|     public static function unknownColumnType($name)
      266|     {                                                                                                                                                                                                         
    &gt; 267|         return new self('Unknown column type "' . $name . '" requested. Any Doctrine type that you use has ' .                                                                                                
      268|             'to be registered with \Doctrine\DBAL\Types\Type::addType(). You can get a list of all the ' .                                                                                                    
      269|             'known types with \Doctrine\DBAL\Types\Type::getTypesMap(). If this error occurs during database ' .                                                                                              
      270|             'introspection then you might have forgotten to register all database types for a Doctrine Type. Use ' .                                                                                          
      271|             'AbstractPlatform#registerDoctrineTypeMapping() or have your custom types implement ' .                                                                                                           
  </code></pre>
  
  <p>Usually I do not  any problem with timestamp fields and I suppose that method ->change  raised this problem.
  How to fix it ?</p>
  
  <p><strong>MODIFIED BLOCK # 1 :</strong>
  I have it istalled 
  my  composer.json :</p>
  
  <pre><code>{
      "name": "laravel/laravel",
      "type": "project",
      "description": "The Laravel Framework.",
      "keywords": [
          "framework",
          "laravel"
      ],
      "license": "MIT",
      "require": {
          "php": "^7.1.3",
          "doctrine/dbal": "^2.9",
          "fideloper/proxy": "^4.0",
          "laravel/framework": "5.7.*",
          "laravel/tinker": "^1.0",
          "marktopper/doctrine-dbal-timestamp-type": "^1.0",
          "mews/purifier": "^2.1",
          "proengsoft/laravel-jsvalidation": "&gt;2.2.0",
          "yajra/laravel-datatables-oracle": "~8.0"
      },
      "require-dev": {
          "beyondcode/laravel-dump-server": "^1.0",
          "filp/whoops": "^2.0",
          "fzaninotto/faker": "^1.4",
          "mockery/mockery": "^1.0",
          "nunomaduro/collision": "^2.0",
          "phpunit/phpunit": "^7.0"
      },
      "config": {
          "optimize-autoloader": true,
          "preferred-install": "dist",
          "sort-packages": true
      },
      "extra": {
          "laravel": {
              "dont-discover": []
          }
      },
      "autoload": {
          "psr-4": {
              "App\\": "app/"
          },
          "classmap": [
              "database/seeds",
              "database/factories"
          ]
      },
      "autoload-dev": {
          "psr-4": {
              "Tests\\": "tests/"
          }
      },
      "minimum-stability": "dev",
      "prefer-stable": true,
      "scripts": {
          "post-autoload-dump": [
              "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
              "@php artisan package:discover --ansi"
          ],
          "post-root-package-install": [
              "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
          ],
          "post-create-project-cmd": [
              "@php artisan key:generate --ansi"
          ]
      }
  }
  </code></pre>
  
  <p>Googling I found that I need also to install marktopper/doctrine-dbal-timestamp-type
  <a href="https://github.com/art-institute-of-chicago/data-aggregator/commit/581f4f318468681c71c62103280daedc67bbe118" rel="nofollow noreferrer">https://github.com/art-institute-of-chicago/data-aggregator/commit/581f4f318468681c71c62103280daedc67bbe118</a>
  I installed it and I do not have error running migration, but created_at default timestamp is NOT defined, so added new row has null in created_at.</p>
  
  <pre><code>$ php artisan --version
  Laravel Framework 5.7.21
  $ node -v 
  v10.15.0
  $ npm -v 
  6.5.0
  </code></pre>
  
  <p>Thanks!</p>