Add /api/notes to get and post notes

notes/api_views.py

@@ -0,0 +1,12 @@
+from django.utils import timezone
+from rest_framework import generics
+
+from notes.models import Note
+from notes.serializers import NoteSerializer
+
+
+class NoteListView(generics.ListCreateAPIView):
+    serializer_class = NoteSerializer
+
+    def get_queryset(self):
+        return Note.objects.filter(to_user=self.request.user, expiry__gt=timezone.now()).select_related("from_user", "to_user")