Refactored json storage

lib/repositories/transactions/models/transactions.dart

@@ -0,0 +1,29 @@
+import 'package:tunas/repositories/json/models/json.dart';
+import 'package:tunas/repositories/transactions/models/transaction.dart';
+
+class Transactions implements Json {
+  List<Transaction> transactions;
+
+  Transactions({
+    this.transactions = const [],
+  });
+  
+  @override
+  Map<String, dynamic> toJson() => {
+    'transactions': transactions.map((transaction) => transaction.toJson()).toList(),
+  };
+  
+  @override
+  String getJsonFileName() {
+    return 'transactions.json';
+  }
+}
+
+class TransactionsFactory implements JsonFactory<Transactions> {
+  @override
+  Transactions fromJson(Map<String, dynamic> json) {
+    return Transactions(
+      transactions: List<Transaction>.from(json['transactions']?.map((transaction) => Transaction.fromJson(transaction))),
+    );
+  }
+}