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/groups.ts

@@ -0,0 +1,18 @@
+import express from 'express'
+import { getAllGroupsHandler, getGroupHandler } from '../controllers/groups.js';
+const router = express.Router({ mergeParams: true });
+
+// root endpoint used to search objects
+router.get('/', getAllGroupsHandler);
+
+// information about a group (members, ... [TODO DOC])
+router.get('/:groupid', getGroupHandler);
+
+// the list of questions a group has made
+router.get('/:id/question', (req, res) => {
+    res.json({
+        questions: [ '0' ],
+    });
+})
+
+export default router