core(major): add api for most simple objects

passbook/core/api/invitations.py

@@ -0,0 +1,18 @@
+from rest_framework.serializers import ModelSerializer
+from rest_framework.viewsets import ModelViewSet
+
+from passbook.core.models import Invitation
+
+
+class InvitationSerializer(ModelSerializer):
+
+    class Meta:
+
+        model = Invitation
+        fields = ['pk', 'expires', 'fixed_username', 'fixed_email', 'needs_confirmation']
+
+
+class InvitationViewSet(ModelViewSet):
+
+    queryset = Invitation.objects.all()
+    serializer_class = InvitationSerializer