feat: add user submission functionality

src/modules/submissions/dtos/answer-submission.dto.ts

@@ -0,0 +1,15 @@
+import { IsNumber, IsOptional } from 'class-validator';
+import { SubmissionAnswer } from '../decorators/submission-answer.decorator';
+
+export class AnswerSubmissionDTO {
+  @IsNumber()
+  @IsOptional()
+  choiceId?: number;
+
+  @IsNumber()
+  @IsOptional()
+  numericValue?: number;
+
+  @SubmissionAnswer()
+  private readonly _submissionAnswerValidation!: never;
+}