Add crosslinks to lessons

docs/en/00_Getting_Started/index.md

@@ -64,6 +64,15 @@ ready for download or installation on a cloud platform.
 If you run into trouble, see [common-problems](installation/common_problems) or post to the 
 [SilverStripe forums](http://silverstripe.org/community/forums/).
 
-## Related
+
+## Related Lessons
+* [Up and running](https://www.silverstripe.org/learn/lessons/v4/up-and-running-setting-up-a-local-silverstripe-dev-environment-1)
+* [Creating your first theme](https://www.silverstripe.org/learn/lessons/v4/creating-your-first-theme-1)
+* [Migrating static templates into your theme](https://www.silverstripe.org/learn/lessons/v4/migrating-static-templates-into-your-theme-1)
+* [Working with multiple templates](https://www.silverstripe.org/learn/lessons/v4/working-with-multiple-templates-1)
+
+## Related Documentation
 
  * [Module installation](/developer_guides/extending/modules)
+
+

docs/en/02_Developer_Guides/00_Model/01_Data_Model_and_ORM.md

@@ -744,6 +744,11 @@ record #2 in Page refers to the same object as record #2 in [SiteTree](api:Silve
 
 To retrieve a news article, SilverStripe joins the [SiteTree](api:SilverStripe\CMS\Model\SiteTree), [Page](api:SilverStripe\CMS\Model\SiteTree\Page) and NewsPage tables by their ID fields. 
 
+## Related Lessons
+* [Introduction to the ORM](https://www.silverstripe.org/learn/lessons/v4/introduction-to-the-orm-1)
+* [Adding custom fields to a page](https://www.silverstripe.org/learn/lessons/v4/adding-custom-fields-to-a-page-1)
+
+
 ## Related Documentation
 
 * [Data Types and Casting](/developer_guides/model/data_types_and_casting)

docs/en/02_Developer_Guides/00_Model/02_Relations.md

@@ -479,6 +479,10 @@ As these lists are not backed by the database, most of the filtering methods on
 this type. As such, an `UnsavedRelationList` should only be used for setting a relation before saving an object, not 
 for displaying the objects contained in the relation.
 
+## Related Lessons
+* [Working with data relationships -- has_many](https://www.silverstripe.org/learn/lessons/v4/working-with-data-relationships-has-many-1)
+* [Working with data relationships -- many_many](https://www.silverstripe.org/learn/lessons/v4/working-with-data-relationships-many-many-1)
+
 ## Related Documentation
 
 * [Introduction to the Data Model and ORM](data_model_and_orm)

docs/en/02_Developer_Guides/00_Model/03_Lists.md

@@ -92,6 +92,9 @@ echo $list->Count();
 // returns '2'
 ```
 
+## Related Lessons
+* [Lists and pagination](https://www.silverstripe.org/learn/lessons/v4/lists-and-pagination-1)
+
 ## API Documentation
 
 * [SS_List](api:SilverStripe\ORM\SS_List)

docs/en/02_Developer_Guides/00_Model/05_Extending_DataObjects.md

@@ -89,3 +89,6 @@ class Player extends DataObject
 Note: There are no separate methods for *onBeforeCreate* and *onBeforeUpdate*. Please check `$this->isInDb()` to toggle 
 these two modes, as shown in the example above.
 </div>
+
+## Related Lessons
+* [Working with data relationships - $has_many](https://www.silverstripe.org/learn/lessons/v4/working-with-data-relationships-has-many-1)

docs/en/02_Developer_Guides/00_Model/06_SearchFilters.md

@@ -61,6 +61,10 @@ $players = Player::get()->filter([
 ]);
 ```
 
+## Related Lessons
+* [Introduction to ModelAdmin](https://www.silverstripe.org/learn/lessons/v4/introduction-to-modeladmin-1)
+* [Building a search form](https://www.silverstripe.org/learn/lessons/v4/building-a-search-form-1)
+
 ## API Documentation
 
 * [SearchFilter](api:SilverStripe\ORM\Filters\SearchFilter)

docs/en/02_Developer_Guides/00_Model/08_SQL_Select.md

@@ -291,7 +291,11 @@ $players = Player::get();
 $map = $players->map('Name', 'NameWithBirthyear');
 ```
 
-## Related
+## Related Lessons
+* [Building custom SQL](https://www.silverstripe.org/learn/lessons/v4/beyond-the-orm-building-custom-sql-1)
+
+
+## Related Documentation
 
 * [Introduction to the Data Model and ORM](data_model_and_orm)
 

docs/en/02_Developer_Guides/00_Model/09_Validation.md

@@ -45,6 +45,9 @@ class MyObject extends DataObject
 }
 ```
 
+## Related Lessons
+* [The holder/page pattern](https://www.silverstripe.org/learn/lessons/v4/the-holderpage-pattern-1)
+
 ## API Documentation
 
 * [DataObject](api:SilverStripe\ORM\DataObject)

docs/en/02_Developer_Guides/01_Templates/01_Syntax.md

@@ -551,7 +551,10 @@ for adding notes for other developers but for things you don't want published in
 $EditForm <%-- Some hidden comment about the form --%>
 ```
 
-## Related
+## Related Lessons
+* [Creating your first theme](https://www.silverstripe.org/learn/lessons/v4/creating-your-first-theme-1)
+
+## Related Documentation
 
 [CHILDREN]
 
@@ -563,3 +566,5 @@ $EditForm <%-- Some hidden comment about the form --%>
 
 * [SSViewer](api:SilverStripe\View\SSViewer)
 * [ThemeManifest](api:SilverStripe\View\ThemeManifest)
+
+

docs/en/02_Developer_Guides/01_Templates/02_Common_Variables.md

@@ -365,7 +365,10 @@ Placing it just below `$Content` is a good default.
 You can add your own forms by implementing new form instances (see the [Forms tutorial](/tutorials/forms)).
 
 
-## Related
+## Related Lessons
+* [Adding dynamic content](https://www.silverstripe.org/learn/lessons/v4/adding-dynamic-content-1)
+
+## Related Documentation
 
  * [Casting and Formating Variables](casting)
  * [Template Inheritance](template_inheritance)

docs/en/02_Developer_Guides/01_Templates/03_Requirements.md

@@ -392,6 +392,10 @@ $file = ModuleResourceLoader::singleton()
   ->resolveURL('silverstripe/admin:client/dist/images/spinner.gif');
 ```
 
+## Related Lessons
+* [Creating your first theme](https://www.silverstripe.org/learn/lessons/v4/creating-your-first-theme-1)
+* [AJAX behaviour and ViewableData](https://www.silverstripe.org/learn/lessons/v4/ajax-behaviour-and-viewabledata-1)
+
 ## API Documentation
 
  * [Requirements](api:SilverStripe\View\Requirements)

docs/en/02_Developer_Guides/01_Templates/04_Rendering_Templates.md

@@ -99,3 +99,9 @@ class PageController extends ContentController
 }
 
 ```
+
+## Related Lessons
+* [Controller actions/DataObjects as pages](https://www.silverstripe.org/learn/lessons/v4/controller-actions-dataobjects-as-pages-1)
+* [AJAX behaviour and ViewableData](https://www.silverstripe.org/learn/lessons/v4/ajax-behaviour-and-viewabledata-1)
+* [Dealing with arbitrary template data](https://www.silverstripe.org/learn/lessons/v4/dealing-with-arbitrary-template-data-1)
+* [Creating filtered views](https://www.silverstripe.org/learn/lessons/v4/creating-filtered-views-1)

docs/en/02_Developer_Guides/01_Templates/05_Template_Inheritance.md

@@ -180,3 +180,6 @@ Module names are derived their local `composer.json` files using the following p
 * The value of the `name` attribute in `composer.json`
 * The value of `extras.installer_name` in `composer.json`
 * The basename of the directory that contains the module
+
+## Related Lessons
+* [Working with multiple templates](https://www.silverstripe.org/learn/lessons/v4/working-with-multiple-templates-1)

docs/en/02_Developer_Guides/01_Templates/06_Themes.md

@@ -103,3 +103,6 @@ The final step is to [submit your theme to Packagist](https://packagist.org/abou
  * [Themes Listing on silverstripe.org](http://addons.silverstripe.org/add-ons?search=&type=theme)
  * [Themes Forum on silverstripe.org](https://www.silverstripe.org/community/forums/themes-2/)
  * [Themes repositories on github.com](http://github.com/silverstripe-themes)
+
+## Related Lessons
+* [Creating your first theme](https://www.silverstripe.org/learn/lessons/v4/creating-your-first-theme-1)

docs/en/02_Developer_Guides/01_Templates/09_Casting.md

@@ -167,3 +167,7 @@ Text / HTMLText methods:
   version of emails.
 * `$LimitSentences(<num>)` Will limit to the first `<num>` sentences in the content. If called on
   HTML content this will have all HTML stripped and converted to plain text.
+
+## Related Lessons
+* [Dealing with arbitrary template data](https://www.silverstripe.org/learn/lessons/v4/dealing-with-arbitrary-template-data-1)
+  

docs/en/02_Developer_Guides/01_Templates/How_Tos/02_Pagination.md

@@ -113,6 +113,8 @@ list.
 | `$Link` | Links to the current controller URL, setting this page as current via a GET parameter |
 | `$CurrentBool` | Returns true if you're currently on that page |
 
+## Related Lessons
+* [Lists and pagination](https://www.silverstripe.org/learn/lessons/v4/lists-and-pagination-1)
 
 ## API Documentation
 

docs/en/02_Developer_Guides/02_Controllers/01_Introduction.md

@@ -174,6 +174,10 @@ public function Link($action = null)
 The [Controller::join_links()](api:SilverStripe\Control\Controller::join_links()) is optional, but makes `Link()` more flexible by allowing an `$action` argument, and concatenates the path segments with slashes. The action should map to a method on your controller.
 </div>
 
+## Related Lessons
+* [Controller actions/DataObjects as pages](https://www.silverstripe.org/learn/lessons/v4/controller-actions-dataobjects-as-pages-1)
+* [Creating filtered views](https://www.silverstripe.org/learn/lessons/v4/creating-filtered-views-1)
+
 ## Related Documentation
 
 * [Execution Pipeline](../execution_pipeline)

docs/en/02_Developer_Guides/02_Controllers/02_Routing.md

@@ -213,6 +213,9 @@ Director:
     'feed': 'FeedController'
 ```
 
+## Related Lessons
+* [Creating filtered views](https://www.silverstripe.org/learn/lessons/v4/creating-filtered-views-1)
+
 ## Links
 
 * [Controller](api:SilverStripe\Control\Controller) API documentation

docs/en/02_Developer_Guides/03_Forms/00_Introduction.md

@@ -346,6 +346,9 @@ $validator = new SilverStripe\Forms\RequiredFields([
 $form = new Form($this, 'MyForm', $fields, $actions, $validator);
 ```
 
+## Related Lessons
+* [Intoduction to frontend forms](https://www.silverstripe.org/learn/lessons/v4/introduction-to-frontend-forms-1)
+
 ## API Documentation
 
 * [Form](api:SilverStripe\Forms\Form)

docs/en/02_Developer_Guides/03_Forms/01_Validation.md

@@ -307,6 +307,10 @@ class Page extends SiteTree
 
 ```
 
+## Related Lessons
+* [Intoduction to frontend forms](https://www.silverstripe.org/learn/lessons/v4/introduction-to-frontend-forms-1)
+
+
 ## API Documentation
 
  * [RequiredFields](api:SilverStripe\Forms\RequiredFields)

docs/en/02_Developer_Guides/04_Configuration/00_Configuration.md

@@ -351,3 +351,6 @@ That is, the fragment will be included if all Only rules match, except if all Ex
 ## API Documentation
 
 * [Config](api:SilverStripe\Core\Config\Config)
+
+## Related Lessons
+* [DataExtensions and SiteConfig](https://www.silverstripe.org/learn/lessons/v4/data-extensions-and-siteconfig-1)

docs/en/02_Developer_Guides/04_Configuration/01_SiteConfig.md

@@ -81,3 +81,7 @@ provide the users a place to configure settings then the `SiteConfig` panel is t
 ## API Documentation
 
 * [SiteConfig](api:SilverStripe\SiteConfig\SiteConfig)
+
+
+## Related Lessons
+* [DataExtensions and SiteConfig](https://www.silverstripe.org/learn/lessons/v4/data-extensions-and-siteconfig-1)

docs/en/02_Developer_Guides/04_Configuration/03_Environment_Variables.md

@@ -11,3 +11,7 @@ For more information see our docs on [Environment Management](../../getting_star
 
 Data which isn't sensitive that can be in version control but is mostly static such as constants is best suited to be 
 included through the [Configuration API](configuration) based on the standard environment types (dev / test / live).
+
+## Related Lessons
+* [Up and running](https://www.silverstripe.org/learn/lessons/v4/up-and-running-setting-up-a-local-silverstripe-dev-environment-1)
+* [Advanced environment configuration](https://www.silverstripe.org/learn/lessons/v4/advanced-environment-configuration-1)

docs/en/02_Developer_Guides/05_Extending/01_Extensions.md

@@ -311,6 +311,10 @@ public function getCMSFields()
 }
 ```
 
+## Related Lessons
+* [DataExtensions and SiteConfig](https://www.silverstripe.org/learn/lessons/v4/data-extensions-and-siteconfig-1)
+
+
 ## Related Documentaion
 
 * [Injector](injector/)

docs/en/02_Developer_Guides/07_Debugging/00_Environment_Types.md

@@ -81,4 +81,5 @@ if (Director::isLive()) {
 }
 ```
 
-
+## Related Lessons
+* [Advanced environment configuration](https://www.silverstripe.org/learn/lessons/v4/advanced-environment-configuration-1)

docs/en/02_Developer_Guides/07_Debugging/01_Error_Handling.md

@@ -265,3 +265,6 @@ In SilverStripe 3, logging was based on the Zend Log module. Customisations were
 This function no longer works, and any Zend Log writers will need to be replaced with Monolog handlers. Fortunately,
 a range of handlers are available, both in the core package and in add-ons. See the
 [Monolog documentation](https://github.com/Seldaek/monolog/blob/master/doc/01-usage.md) for more information.
+
+## Related Lessons
+* [Advanced environment configuration](https://www.silverstripe.org/learn/lessons/v4/advanced-environment-configuration-1)

docs/en/02_Developer_Guides/14_Files/01_File_Management.md

@@ -202,3 +202,6 @@ storage.
 SilverStripe\Assets\File:
   keep_archived_assets: true
 ```
+
+## Related Lessons
+* [Working with files and images](https://www.silverstripe.org/learn/lessons/v4/working-with-files-and-images-1)

docs/en/02_Developer_Guides/14_Files/02_Images.md

@@ -214,3 +214,7 @@ SilverStripe\Core\Injector\Injector:
  * [Image](api:SilverStripe\Assets\Image)
  * [DBFile](api:SilverStripe\Assets\Storage\DBFile)
  * [ImageManipulation](api:SilverStripe\Assets\ImageManipulation)
+
+## Related Lessons
+* [Working with files and images](https://www.silverstripe.org/learn/lessons/v4/working-with-files-and-images-1)
+ 

docs/en/02_Developer_Guides/15_Customising_the_Admin_Interface/01_ModelAdmin.md

@@ -360,6 +360,9 @@ class MyAdmin extends ModelAdmin
 }
 ```
 
+## Related Lessons
+* [Intoduction to ModelAdmin](https://www.silverstripe.org/learn/lessons/v4/introduction-to-modeladmin-1)
+
 ## Related Documentation
 
 * [GridField](../forms/field_types/gridfield)