Make entity property virtual.

https://github.com/abpframework/abp/pull/2900#issuecomment-590256111

framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/Auditing/FullAuditedAggregateRootWithUser.cs

@@ -15,10 +15,10 @@ namespace Volo.Abp.Domain.Entities.Auditing
         public virtual TUser Deleter { get; set; }
 
         /// <inheritdoc />
-        public TUser Creator { get; set; }
+        public virtual TUser Creator { get; set; }
 
         /// <inheritdoc />
-        public TUser LastModifier { get; set; }
+        public virtual TUser LastModifier { get; set; }
     }
 
     /// <summary>
@@ -34,10 +34,10 @@ namespace Volo.Abp.Domain.Entities.Auditing
         public virtual TUser Deleter { get; set; }
 
         /// <inheritdoc />
-        public TUser Creator { get; set; }
+        public virtual TUser Creator { get; set; }
 
         /// <inheritdoc />
-        public TUser LastModifier { get; set; }
+        public virtual TUser LastModifier { get; set; }
 
         protected FullAuditedAggregateRootWithUser()
         {

framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/Auditing/FullAuditedEntityWithUser.cs

@@ -15,10 +15,10 @@ namespace Volo.Abp.Domain.Entities.Auditing
         public virtual TUser Deleter { get; set; }
 
         /// <inheritdoc />
-        public TUser Creator { get; set; }
+        public virtual TUser Creator { get; set; }
 
         /// <inheritdoc />
-        public TUser LastModifier { get; set; }
+        public virtual TUser LastModifier { get; set; }
     }
 
     /// <summary>
@@ -34,10 +34,10 @@ namespace Volo.Abp.Domain.Entities.Auditing
         public virtual TUser Deleter { get; set; }
 
         /// <inheritdoc />
-        public TUser Creator { get; set; }
+        public virtual TUser Creator { get; set; }
         
         /// <inheritdoc />
-        public TUser LastModifier { get; set; }
+        public virtual TUser LastModifier { get; set; }
 
         protected FullAuditedEntityWithUser()
         {