Adds flight,battery models and image file managment

lib/models/battery.dart

@@ -0,0 +1,33 @@
+class Battery {
+  int? id;
+  String name;
+  String type;
+  double voltage;
+  String? imageUuid;
+
+  Battery({
+    this.id,
+    required this.name,
+    required this.type,
+    required this.voltage,
+    this.imageUuid,
+  });
+
+  factory Battery.fromMap(Map<String, dynamic> map) => Battery(
+    id: map["id"],
+    name: map["name"],
+    type: map["type"],
+    voltage: map["voltage"],
+    imageUuid: map["image_uuid"],
+  );
+
+  Map<String, dynamic> toMap() {
+    return {
+      "id": id,
+      "name": name,
+      "type": type,
+      "voltage": voltage,
+      "image_uuid": imageUuid,
+    };
+  }
+}