anchor.diff:  type Model = 
     { WishList : WishList
       Token : string
  -    NewBook: Book
  +    NewBook : Book
  +    NewBookId : Guid // unique key to reset the vdom-elements, see https://github.com/fable-compiler/fable-suave-scaffold/issues/107#issuecomment-301312224
       TitleErrorText : string option
       AuthorsErrorText : string option
       LinkErrorText : string option
  
positive.code:                          yield div [ClassName "input-group"][
                               yield span [ClassName "input-group-addon"] [span [ClassName "glyphicon glyphicon-user"] [] ]
                               yield input [ 
                                       HTMLAttr.Type "text"
                                       Name "Author"
                                       DefaultValue (U2.Case1 model.NewBook.Authors)
  
negative.code:     { WishList = WishList.New user.UserName
        Token = user.Token
        NewBook = Book.empty
        NewBookId = Guid.NewGuid()
        TitleErrorText = None
        AuthorsErrorText = None
        LinkErrorText = None
  