User synchronization revamped.

code/MessengerApi/Models/UserIngestionItem.cs

@@ -0,0 +1,15 @@
+namespace MessengerApi.Models
+{
+    public class UserIngestionItem
+    {
+        public string UserName { get; set; }
+
+        public Guid Id { get; set; }
+
+        public Guid ApiKey { get; set; }
+
+        public bool IsEnabled { get; set; }
+
+        public UserIngestionItem[] CanSendTo { get; set; }
+    }
+}