Added support for YouTube videos

lib/ui/tiles/post_tile.dart

@@ -168,6 +168,10 @@ class _PostTileState extends State<PostTile> {
         postContent = _buildPostImage();
         break;
 
+      case PostKind.YOUTUBE:
+        postContent = _buildPostYouTube();
+        break;
+
       case PostKind.WEB_LINK:
         postContent = _buildPostWebLink();
         break;
@@ -259,6 +263,22 @@ class _PostTileState extends State<PostTile> {
     );
   }
 
+  Widget _buildPostYouTube() {
+    return RaisedButton(
+      color: Colors.red,
+      textColor: Colors.white,
+      child: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: <Widget>[
+          Icon(Icons.ondemand_video),
+          Text(tr("YouTube movie"))
+        ],
+      ),
+      onPressed: () =>
+          launch("https://youtube.com/watch/?v=" + widget.post.filePath),
+    );
+  }
+
   Widget _buildPostWebLink() {
     return Card(
       color: Color.fromRGBO(0xf7, 0xf7, 0xf7, 1),