add discount api

lib/domain/entities/discount.dart

@@ -1,16 +1,38 @@
 class Discount {
+  String id;
   String code;
-  String customer;
+  String customerId;
+  String customerName;
   String status;
   double amount;
-  int weight;
-  double discountRate;
 
-  Discount(
-      {this.code,
-      this.customer,
-      this.amount,
-      this.status,
-      this.weight,
-      this.discountRate});
+  Discount({
+    this.id,
+    this.code,
+    this.customerId,
+    this.customerName,
+    this.amount,
+    this.status,
+  });
+
+  Map<String, dynamic> toMap() {
+    return {
+      'id': id,
+      'code': code,
+      "customer_id": customerId,
+      "customer_name": customerName,
+      "amount": amount,
+    };
+  }
+
+  factory Discount.fromMap(Map<String, dynamic> map, String id) {
+    return Discount(
+      id: id,
+      code: map['code'],
+      customerId: map['customer_id'],
+      customerName: map['customer_name'],
+      amount: map['amount'],
+      status: map['status'],
+    );
+  }
 }