fix: some fixes in example app

lib/interfaces/items.dart

@@ -166,13 +166,14 @@ class GymHistoryItem {
   final String date;
   final String sum;
   final String photo;
+  final String timestamp;
 
-  GymHistoryItem({
-    required this.id,
-    required this.date,
-    required this.sum,
-    required this.photo,
-  });
+  GymHistoryItem(
+      {required this.id,
+      required this.date,
+      required this.sum,
+      required this.photo,
+      required this.timestamp});
 
   factory GymHistoryItem.fromRawJson(String str) =>
       GymHistoryItem.fromJson(json.decode(str));
@@ -184,12 +185,14 @@ class GymHistoryItem {
         date: json["date"],
         sum: json["sum"],
         photo: json["photo"],
+        timestamp: json["timestamp"],
       );
 
   Map<String, dynamic> toJson() => {
         "id": id,
         "date": date,
         "sum": sum,
+        "timestamp": timestamp,
         "photo": photo,
       };
 }
@@ -201,19 +204,20 @@ class GymHistoryItemDetail {
   String? payUrl;
   final String receiver;
   final String email;
+  final String timestamp;
   final String address;
   final List<GymHistoryItemDetailProvider> providers;
 
-  GymHistoryItemDetail({
-    required this.id,
-    required this.date,
-    required this.sum,
-    this.payUrl,
-    required this.providers,
-    required this.receiver,
-    required this.email,
-    required this.address,
-  });
+  GymHistoryItemDetail(
+      {required this.id,
+      required this.date,
+      required this.sum,
+      this.payUrl,
+      required this.providers,
+      required this.receiver,
+      required this.email,
+      required this.address,
+      required this.timestamp});
 
   factory GymHistoryItemDetail.fromRawJson(String str) =>
       GymHistoryItemDetail.fromJson(json.decode(str));
@@ -222,16 +226,16 @@ class GymHistoryItemDetail {
 
   factory GymHistoryItemDetail.fromJson(Map<String, dynamic> json) =>
       GymHistoryItemDetail(
-        id: json["id"],
-        date: json["date"],
-        sum: json["sum"],
-        receiver: json["receiver"],
-        email: json["email"],
-        address: json["address"],
-        payUrl: json["pay_url"] as String?,
-        providers: List<GymHistoryItemDetailProvider>.from(json["providers"]
-            .map((x) => GymHistoryItemDetailProvider.fromJson(x))),
-      );
+          id: json["id"],
+          date: json["date"],
+          sum: json["sum"],
+          receiver: json["receiver"],
+          email: json["email"],
+          address: json["address"],
+          payUrl: json["pay_url"] as String?,
+          providers: List<GymHistoryItemDetailProvider>.from(json["providers"]
+              .map((x) => GymHistoryItemDetailProvider.fromJson(x))),
+          timestamp: json["timestamp"]);
 
   Map<String, dynamic> toJson() => {
         "id": id,
@@ -241,6 +245,7 @@ class GymHistoryItemDetail {
         "providers": List<dynamic>.from(providers.map((x) => x.toJson())),
         "receiver": receiver,
         "email": email,
+        "timestamp": timestamp,
         "address": address,
       };
 }