fix(backend): group toch niet deel van primaire sleutel van vragen en submissions gemaakt, maar verplicht veld

backend/src/entities/assignments/submission.entity.ts

@@ -22,8 +22,7 @@ export class Submission {
     submissionNumber?: number;
 
     @ManyToOne({
-        entity: () => Group,
-        primary: true
+        entity: () => Group
     })
     onBehalfOf!: Group;
 

backend/src/entities/questions/question.entity.ts

@@ -21,7 +21,7 @@ export class Question {
     @PrimaryKey({ type: 'integer', autoincrement: true })
     sequenceNumber?: number;
 
-    @ManyToOne({ entity: () => Group, primary: true })
+    @ManyToOne({ entity: () => Group })
     inGroup!: Group;
 
     @ManyToOne({