added a model for groups

backend/pigeonhole/apps/groups/models.py

@@ -0,0 +1,17 @@
+from django.db import models
+from rest_framework import serializers
+
+from backend.pigeonhole.apps.projects.models import Project
+
+
+class Group(models.Model):
+    group_id = models.BigAutoField(primary_key=True)
+    group_nr = models.IntegerField()
+    final_score = models.IntegerField()
+    project_id = models.ForeignKey(Project, on_delete=models.CASCADE)
+
+
+class GroupSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Group
+        fields = ["group_id", "group_nr", "final_score", "project_id"]