feat: add user submission functionality

src/modules/submissions/entities/submission.entity.ts

@@ -6,18 +6,20 @@ import {
   Entity,
   ManyToOne,
   OneToMany,
+  OneToOne,
   PrimaryGeneratedColumn,
 } from 'typeorm';
 import { SubmissionStatus } from '../enums/submission-status.enum';
 import { SubmissionAnswer } from './submission-answer.entity';
+import { SubmissionResult } from './submission-result.entity';
 
 @Entity()
 export class Submission {
   @PrimaryGeneratedColumn()
   id!: number;
 
-  @ManyToOne(() => User, { nullable: true, onDelete: 'SET NULL' })
-  user?: User;
+  @ManyToOne(() => User, { onDelete: 'CASCADE' })
+  user!: User;
 
   @ManyToOne(() => Test, { onDelete: 'CASCADE' })
   test!: Test;
@@ -32,6 +34,9 @@ export class Submission {
   @OneToMany(() => SubmissionAnswer, (answer) => answer.submission)
   answers!: Array<SubmissionAnswer>;
 
+  @OneToOne(() => SubmissionResult, (result) => result.submission)
+  result?: SubmissionResult;
+
   @CreateDateColumn()
   createdAt!: Date;
 }