Display published at date for news articles (#310)

lib/assets/components/explore_tiles.dart

@@ -348,7 +348,7 @@ class ExploreNewsArticleTile extends ExploreTile {
                           .apply(fontStyle: FontStyle.normal),
                     ),
                     Text(
-                      article.releasedAt.let(DateFormat('d MMM y').format),
+                      article.publishedAt.let(DateFormat('d MMM y').format),
                     ),
                   ],
                 ),

lib/models/article.dart

@@ -26,6 +26,7 @@ class NewsArticle implements Explorable {
   final String subtitle;
   final Api.Image headerImage;
   final DateTime releasedAt;
+  final DateTime publishedAt;
   final Uri link;
 
   NewsArticle({
@@ -34,6 +35,7 @@ class NewsArticle implements Explorable {
     required this.subtitle,
     required this.headerImage,
     required this.releasedAt,
+    required this.publishedAt,
     required this.link,
   });
 
@@ -43,6 +45,7 @@ class NewsArticle implements Explorable {
         subtitle = apiModel.subtitle,
         headerImage = apiModel.headerImage,
         releasedAt = apiModel.releaseAt,
+        publishedAt = apiModel.publishedAt,
         link = Uri.parse(apiModel.link);
 
   String get shortUrl => link.host;

test/factories/article_factory.dart

@@ -13,6 +13,7 @@ class ArticleFactory extends ModelFactory<NewsArticle> {
       headerImage: ImageFactory().generate(),
       link: Uri.parse(faker.internet.httpsUrl()),
       releasedAt: faker.date.dateTime(),
+      publishedAt: faker.date.dateTime(),
     );
   }
 }