fix: interface bestanden enkelvoud

backend/src/interfaces/assignment.ts

@@ -1,6 +1,6 @@
 import { Assignment } from "../entities/assignments/assignment.entity";
 import { Class } from "../entities/classes/class.entity";
-import { GroupDTO } from "./groups";
+import { GroupDTO } from "./group";
 
 export interface AssignmentDTO {
     id: number,
@@ -22,4 +22,4 @@ export function mapToAssignmentDTO(assignment: Assignment, cls: Class): Assignme
         language: assignment.learningPathLanguage,
         //groups: assignment.groups.map(mapToGroupDTO),
     };
-}
+}