add methods in Repository and Model for importing data

kontor-gin/internal/repository/assignment.go

@@ -35,3 +35,26 @@ func (repository *AssignmentRepository) GetById(context context.Context, id stri
 	}
 	return assignment, result.Error
 }
+
+func (repository *AssignmentRepository) Import(assignments models.AssignmentDTOList) {
+	slog.Info("AssignmentRepository#Import")
+	for index, assignment := range assignments {
+		slog.Info("importing", "index", index, "profile", assignment)
+		model := assignment.ConvertDTOToModel()
+		existing_item := models.Assignment{ID: assignment.ID}
+		result_existing := repository.db.First(&existing_item)
+		if result_existing.Error != nil {
+			slog.Info("check existing id: not found - inserting")
+			result := repository.db.Create(&model)
+			if result.Error != nil {
+				slog.Info("error during import", "error", result.Error.Error())
+			}
+		} else {
+			slog.Info("check existing id: found - updating")
+			result := repository.db.Save(&model)
+			if result.Error != nil {
+				slog.Info("error during updating", "error", result.Error.Error())
+			}
+		}
+	}
+}