added categories, import export, settings

lib/models/supermarket.dart

@@ -0,0 +1,59 @@
+/// A user-defined supermarket with a display color.
+library;
+
+import 'package:flutter/material.dart';
+
+class Supermarket {
+  const Supermarket({
+    this.id,
+    required this.name,
+    required this.colorValue,
+    this.sortOrder = 0,
+  });
+
+  final int? id;
+  final String name;
+  final int colorValue;
+  final int sortOrder;
+
+  Color get color => Color(colorValue);
+
+  factory Supermarket.fromMap(Map<String, Object?> map) {
+    return Supermarket(
+      id: map['id'] as int?,
+      name: map['name']! as String,
+      colorValue: map['color']! as int,
+      sortOrder: map['sort_order'] as int? ?? 0,
+    );
+  }
+
+  Supermarket copyWith({
+    int? id,
+    String? name,
+    int? colorValue,
+    int? sortOrder,
+  }) {
+    return Supermarket(
+      id: id ?? this.id,
+      name: name ?? this.name,
+      colorValue: colorValue ?? this.colorValue,
+      sortOrder: sortOrder ?? this.sortOrder,
+    );
+  }
+}
+
+/// Palette offered when the user picks a store color.
+const List<int> kStoreColorPalette = [
+  0xFFEEC21B, // Jumbo yellow
+  0xFF0050AA, // Lidl blue
+  0xFF00A0E2, // AH blue
+  0xFF00205B, // Aldi navy
+  0xFF6EC31E, // Plus green
+  0xFFE30613, // Dirk / Coop red
+  0xFF009640, // SPAR green
+  0xFFE87722, // orange
+  0xFFE31C5F, // Picnic pink
+  0xFF7B1FA2, // purple
+  0xFF00897B, // teal
+  0xFF78909C, // grey
+];