added update for the env-plugin section

src/content/docs/guides/using-plugins.mdx

@@ -300,7 +300,7 @@ container or the scoped container.
 Here is an example of the TMDB feature that uses the `init()` to register some
 feature-level dependencies:
 
-```dart {8-10}
+```dart {8-10} title="feature_tmdb/feature.dart"
 final feature = FeatureDescriptor(
   name: 'tmdb',
   title: 'TMDB',
@@ -327,7 +327,44 @@ TBD
 
 ## Using the `EnvPlugin`
 
-TBD
+The env plugin is useful for loading environment settings from a `.env` file. We
+use the `flutter_dotenv` package from _pub.dev_ to load these settings. The
+env-plugin makes it convenient for us to load it up automatically and make it
+available on `vyuh.env`.
+
+The plugin assumes that you have a `.env` file in your application package which
+is loaded automatically at runtime. Also, make sure to include it in your assets
+section of `pubspec.yaml`.
+
+```yaml {4} title="pubspec.yaml"
+flutter:
+  uses-material-design: true
+  assets:
+    - .env
+    - assets/app-icon.png
+```
+
+As an example, notice how the TMDB feature uses the env plugin to load the
+`TMDB_ API_KEY` in the `init()` method.
+
+```dart {8} title="feature_tmdb/feature.dart"
+final feature = FeatureDescriptor(
+  name: 'tmdb',
+  title: 'TMDB',
+  description:
+      'Uses the TMDB API to show details of movies with ability to favorite and add to watchlists',
+  icon: Icons.movie_creation_outlined,
+  init: () async {
+    final apiKey = vyuh.env.get('TMDB_API_KEY');
+
+    vyuh.di.register(TMDBClient(apiKey));
+
+    // Rest of the init
+  },
+
+  // rest of the feature config
+);
+```
 
 ## Using the `EventPlugin`