feat(back-end): Implement notification logic

Add models, repository, controller, hub and migration to implement the logic of notifications

Domain/Data/ApplicationDbContext.cs

@@ -52,5 +52,7 @@ protected override void OnModelCreating(ModelBuilder builder)
         public DbSet<DayStatistics> DayStatistics { get; set; }
         public DbSet<MonthStatistics> MonthStatistics { get; set; }
         public DbSet<YearStatistics> YearStatistics { get; set; }
+
+        public DbSet<Notification> Notifications { get; set; }
     }
 }

Domain/Entities/Notification.cs

@@ -0,0 +1,28 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Kaizen.Domain.Entities
+{
+    public enum NotificationState
+    {
+        Pending,
+        View
+    }
+
+    public class Notification
+    {
+        [Key]
+        public int Id { get; set; }
+
+        public string Title { get; set; }
+        public string Message { get; set; }
+        public string Icon { get; set; }
+
+        public NotificationState State { get; set; } = NotificationState.Pending;
+
+        [ForeignKey("UserId")]
+        public ApplicationUser User { get; set; }
+
+        public string UserId { get; set; }
+    }
+}