Infrastructure for whiteboard membership entity

dotnet/AipsCore/Infrastructure/Persistence/WhiteboardMembership/WhiteboardMembership.cs

@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace AipsCore.Infrastructure.Persistence.WhiteboardMembership;
+
+public class WhiteboardMembership 
+{
+    [Key]
+    public Guid Id { get; set; }
+    
+    public Guid WhiteboardId { get; set; }
+
+    public Whiteboard.Whiteboard? Whiteboard { get; set; } = null!;
+    
+    public Guid UserId { get; set; }
+
+    public User.User? User { get; set; } = null!;
+    
+    public bool IsBanned { get; set; }
+    
+    public bool EditingEnabled { get; set; }
+    
+    public bool CanJoin { get; set; }
+    
+    public DateTime LastInteractedAt { get; set; }
+}