add django backend in /core

ported from laravel in c3lf/lfbackend repo

core/files/api_v1.py

@@ -0,0 +1,25 @@
+from rest_framework import serializers, viewsets, routers
+
+from files.models import File
+
+
+class FileSerializer(serializers.ModelSerializer):
+    data = serializers.CharField(max_length=1000000, write_only=True)
+
+    class Meta:
+        model = File
+        fields = ['hash', 'data']
+        read_only_fields = ['hash']
+
+
+class FileViewSet(viewsets.ModelViewSet):
+    serializer_class = FileSerializer
+    queryset = File.objects.all()
+    lookup_field = 'hash'
+
+
+router = routers.SimpleRouter()
+router.register(r'files', FileViewSet, basename='files')
+router.register(r'file', FileViewSet, basename='files')
+
+urlpatterns = router.urls