update series recordings

MediaBrowser.Controller/LiveTv/LiveTvProgram.cs

@@ -60,6 +60,12 @@ namespace MediaBrowser.Controller.LiveTv
         /// <value><c>true</c> if this instance is repeat; otherwise, <c>false</c>.</value>
         public bool IsRepeat { get; set; }
 
+        /// <summary>
+        /// Gets or sets the external series identifier.
+        /// </summary>
+        /// <value>The external series identifier.</value>
+        public string ExternalSeriesId { get; set; }
+        
         /// <summary>
         /// Gets or sets the episode title.
         /// </summary>