implement client server connection tracking persistence

Data/Models/Client/EFClientConnectionHistory.cs

@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+using Data.Models.Server;
+using Stats.Models;
+
+namespace Data.Models.Client
+{
+    public class EFClientConnectionHistory : AuditFields
+    {
+        [Key] 
+        public long ClientConnectionId { get; set; }
+
+        public int ClientId { get; set; }
+        
+        [ForeignKey(nameof(ClientId))]
+        public EFClient Client { get;set; }
+        
+        public long ServerId { get; set; }
+        
+        [ForeignKey(nameof(ServerId))]
+        public EFServer Server { get;set; }
+        
+        public Reference.ConnectionType ConnectionType { get; set; }
+    }
+}