added Category

lib/client/models/category.dart

@@ -0,0 +1,18 @@
+import 'package:json_annotation/json_annotation.dart';
+
+part 'category.g.dart';
+
+/// based on https://github.com/LemmyNet/lemmy/blob/464ea862b10fa7b226b2550268e40d8e685a939c/server/lemmy_db/src/category.rs#L10
+@JsonSerializable(fieldRename: FieldRename.snake, createToJson: false)
+class Category {
+  final int id;
+  final String name;
+
+  const Category({
+    this.id,
+    this.name,
+  });
+
+  factory Category.fromJson(Map<String, dynamic> json) =>
+      _$CategoryFromJson(json);
+}