Finished module guide [skip ci]

docs/guide/structure-application-components.md

@@ -10,12 +10,15 @@ Each application component has an ID that uniquely identifies itself among other
 in the same application. You can access an application component through the expression
 
 ```php
-\Yii::$app->ComponentID
+\Yii::$app->componentID
 ```
 
 For example, you can use `\Yii::$app->db` to get the [[yii\db\Connection|DB connection]],
 and `\Yii::$app->cache` to get the [[yii\caching\Cache|primary cache]] registered with the application.
 
+An application component is created the first time it is accessed through the above expression. Any
+further accesses will return the same component instance.
+
 Application components can be any objects. You can register them by configuring
 the [[yii\base\Application::components]] property in [application configurations](structure-applications.md#application-configurations).
 For example,
@@ -48,6 +51,29 @@ For example,
   and use it when needed.
 
 
+## Bootstrapping Components <a name="bootstrapping-components"></a>
+
+As mentioned above, an application component will only be instantiated when it is being accessed the first time.
+If it is not accessed at all during a request, it will not be instantiated. Sometimes, however, you may want
+to instantiate an application component for every request, even if it is not explicitly accessed.
+To do so, you may list its ID in the [[yii\base\Application::bootstrap|bootstrap]] property of the application.
+
+For example, the following application configuration makes sure the `log` component is always loaded:
+
+```php
+[
+    'bootstrap' => [
+        'log',
+    ],
+    'components' => [
+        'log' => [
+            // configuration for "log" component
+        ],
+    ],
+]
+```
+
+
 ## Core Application Components <a name="core-application-components"></a>
 
 Yii defines a set of *core* application components with fixed IDs and default configurations. For example,

docs/guide/structure-views.md

@@ -89,7 +89,7 @@ use yii\helpers\HtmlPurifier;
 
 Like [controllers](structure-controllers.md) and [models](structure-models.md), there are conventions to organize views.
 
-* For views rendered in a controller, they should be put under the directory `@app/views/ControllerID` by default,
+* For views rendered by a controller, they should be put under the directory `@app/views/ControllerID` by default,
   where `ControllerID` refers to the [controller ID](structure-controllers.md#routes). For example, if
   the controller class is `PostController`, the directory would be `@app/views/post`; If it is `PostCommentController`,
   the directory would be `@app/views/post-comment`. In case the controller belongs to a module, the directory