feat:增加日程模块

lib/models/Schedule.dart

@@ -0,0 +1,18 @@
+class Schedule {
+  final int id;
+  String title;
+  DateTime startTime;
+  DateTime endTime;
+  DateTime? scheduleDate;
+  DateTime createTime;
+
+  Schedule({
+    int? id,
+    required this.title,
+    required this.startTime,
+    required this.endTime,
+    this.scheduleDate,
+    DateTime? createTime,
+  }) : id = id ?? DateTime.timestamp().microsecond,
+        createTime = DateTime.now();
+}