bring in database

switch to just using source models (no extra db fields)
start re-implementing sync service

test/util/http.dart

@@ -0,0 +1,6 @@
+import 'package:http/http.dart';
+
+class TestHttpClient extends BaseClient {
+  @override
+  Future<StreamedResponse> send(BaseRequest request) => request.send();
+}