feat: submission full backend stack opgekuist

common/src/interfaces/group.ts

@@ -1,7 +1,9 @@
 import { AssignmentDTO } from './assignment';
+import { ClassDTO } from './class';
 import { StudentDTO } from './student';
 
 export interface GroupDTO {
+    class: string | ClassDTO;
     assignment: number | AssignmentDTO;
     groupNumber: number;
     members: string[] | StudentDTO[];