fix: functies binnen teacher invitation repo zijn nu beschikbaar

backend/src/entities/classes/teacher-invitation.entity.ts

@@ -1,11 +1,16 @@
 import { Entity, ManyToOne } from '@mikro-orm/core';
 import { Teacher } from '../users/teacher.entity.js';
 import { Class } from './class.entity.js';
+import { TeacherInvitationRepository } from '../../data/classes/teacher-invitation-repository.js';
 
 /**
  * Invitation of a teacher into a class (in order to teach it).
  */
-@Entity()
+@Entity({
+    repository: () => {
+        return TeacherInvitationRepository;
+    },
+})
 export class TeacherInvitation {
     @ManyToOne({
         entity: () => {