Merge pull request #2117 from umbraco/temp-U4-10201

U4-10201 Exception when deleting a user's start node - adds FKs, fixe…

src/Umbraco.Core/Models/Rdbms/UserGroupDto.cs

@@ -51,10 +51,12 @@ namespace Umbraco.Core.Models.Rdbms
 
         [Column("startContentId")]
         [NullSetting(NullSetting = NullSettings.Null)]
+        [ForeignKey(typeof(NodeDto), Name = "FK_startContentId_umbracoNode_id")]
         public int? StartContentId { get; set; }
 
         [Column("startMediaId")]
         [NullSetting(NullSetting = NullSettings.Null)]
+        [ForeignKey(typeof(NodeDto), Name = "FK_startMediaId_umbracoNode_id")]
         public int? StartMediaId { get; set; }
 
         [ResultColumn]