add structure

lib/vo/inventory_line.dart

@@ -0,0 +1,54 @@
+class InventoryLine {
+  String storageID;
+  String storageName;
+  String productID;
+  String productName;
+  int quantity;
+  int oldQty;
+
+  String action;
+  InventoryLine(
+      {this.storageID,
+      this.storageName,
+      this.productID,
+      this.productName,
+      this.quantity,
+      this.oldQty});
+
+  @override
+  bool operator ==(other) {
+    if (identical(this, other)) {
+      return true;
+    }
+    return (other.storageID == this.storageID &&
+        other.productID == this.productID);
+  }
+
+  @override
+  int get hashCode {
+    int result = 17;
+    result = 37 * result + storageID.hashCode;
+    result = 37 * result + productID.hashCode;
+    return result;
+  }
+
+  Map<String, dynamic> toMap() {
+    return {
+      'storage_id': storageID,
+      'storage_name': storageName,
+      'product_id': productID,
+      'product_name': productName,
+      'quantity': quantity
+    };
+  }
+
+  factory InventoryLine.fromMap(Map<String, dynamic> map) {
+    return InventoryLine(
+      storageID: map['storage_id'],
+      storageName: map['storage_name'],
+      productID: map['product_id'],
+      productName: map['product_name'],
+      quantity: map['quantity'],
+    );
+  }
+}