add methods in Repository and Model for importing data

kontor-gin/internal/models/article.go

@@ -43,6 +43,8 @@ func ConvertArticlesToDtos(articles []Article) []ArticleDTO {
 	return dtos
 }
 
+type ArticleDTOList []ArticleDTO
+
 type CreateArticleDTO struct {
 	Title string `json:"title"                           binding:"required"`
 }