rewrite number whatever to .net and blazor.

Models/Newsletter.cs

@@ -0,0 +1,23 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace landing.Models;
+
+[Table("newsletters")]
+public class Newsletter
+{
+    [Key]
+    [Column("id")]
+    public int Id { get; set; }
+
+    [Required]
+    [Column("subject")]
+    public string Subject { get; set; } = string.Empty;
+
+    [Required]
+    [Column("body")]
+    public string Body { get; set; } = string.Empty;
+
+    [Column("sent_at")]
+    public DateTime SentAt { get; set; } = DateTime.UtcNow;
+}