add support for XWebinarGroupEntity and it's InMemory Repository and also Register it's required Services and usage in WebinarHub ...

Models/Entities/XWebinarGroupEntity.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using xModels.Base;
+using xPushService.Base;
+
+namespace xWebinarService.Models.Entities
+{
+    public class XWebinarGroupEntity : XBaseGuidIDEntity
+    {
+       public Guid WebinarId { get; set; } 
+       public List<XHubConnectionDto> Connections { get; set; } = new List<XHubConnectionDto>();
+    }
+}