Merge branch 'feat/service-layer' into feat/service-layer-adriaan

# Conflicts:
#	backend/src/controllers/classes.ts
#	backend/src/controllers/students.ts
#	backend/src/data/users/teacher-repository.ts
#	backend/src/interfaces/assignment.ts
#	backend/src/interfaces/teacher.ts
#	backend/src/routes/classes.ts
#	backend/src/services/assignments.ts
#	backend/src/services/class.ts
#	backend/src/services/students.ts
#	backend/src/util/translation-helper.ts

backend/src/routes/assignments.ts

@@ -0,0 +1,31 @@
+import express from 'express'
+import { getAllAssignmentsHandler, getAssignmentHandler } from '../controllers/assignments.js';
+import groupRouter from './group.js';
+
+const router = express.Router({ mergeParams: true });
+
+// root endpoint used to search objects
+router.get('/', getAllAssignmentsHandler);
+
+// information about an assignment with id 'id'
+router.get('/:id', getAssignmentHandler);
+
+router.get('/:id/submissions', (req, res) => {
+    res.json({
+        submissions: [
+            '0'
+        ],
+    });
+});
+
+router.get('/:id/questions', (req, res) => {
+    res.json({
+        questions: [
+            '0'
+        ],
+    });
+});
+
+router.use('/:assignmentid/groups', groupRouter);
+
+export default router