i'm sorry guys it's stupid commit...

SurveyBackend/SurveyBackend.API/Mappers/CompletionMapper.cs

@@ -0,0 +1,21 @@
+using SurveyBackend.DTOs.Completion;
+using SurveyLib.Core.Models;
+
+namespace SurveyBackend.Mappers;
+
+public static class CompletionMapper
+{
+    public static Completion CreateDtoToModel(CompletionCreateDto dto, int surveyId, int? performerId) => new Completion
+    {
+        SurveyId = surveyId,
+        CompletedBy = performerId,
+        Answers = dto.Answers.Select(AnswerMapper.CreateDtoToModel).ToList(),
+    };
+
+    public static CompletionOutputDto ModelToOutputDto(Completion model) => new CompletionOutputDto
+    {
+        CompletedBy = model.CompletedBy,
+        FinishedAt = model.FinishedAt,
+        Answers = model.Answers.Select(AnswerMapper.ModelToOutputDto).ToList(),
+    };
+}