feat: Implement a basic anime calendar

lib/src/data/anime.dart

@@ -1,9 +1,20 @@
 import 'package:anitrack/src/data/type.dart';
+import 'package:anitrack/src/service/database.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'anime.freezed.dart';
 part 'anime.g.dart';
 
+class BoolConverter implements JsonConverter<bool, int> {
+  const BoolConverter();
+
+  @override
+  bool fromJson(int json) => json.toBool();
+
+  @override
+  int toJson(bool object) => object.toInt();
+}
+
 /// Data about a tracked anime
 @freezed
 class AnimeTrackingData with _$AnimeTrackingData, TrackingMedium {
@@ -25,6 +36,12 @@ class AnimeTrackingData with _$AnimeTrackingData, TrackingMedium {
 
     /// URL to the thumbnail/cover art for the anime.
     String thumbnailUrl,
+
+    /// Flag whether the anime is airing
+    @BoolConverter() bool airing,
+
+    /// The day of the week the anime is airing
+    String? broadcastDay,
   ) = _AnimeTrackingData;
 
   /// JSON