Add a helper function to ensure we have the correct datastore installed

app/bin/server_common.dart

Index: app/bin/server_common.dart
diff --git a/app/bin/server_common.dart b/app/bin/server_common.dart
index bb3a6b4211911e44910ec05afd5f31fdbfc923ee..a7640f26449804f97c5473592b53180609f71100 100644
--- a/app/bin/server_common.dart
+++ b/app/bin/server_common.dart
@@ -107,3 +107,25 @@ Future<DatastoreDB> initializeApiaryDatastore() async {
 
   return db;
 }
+
+/// Wrapper function used to work around issue with running gRPC datastore on
+/// MacOS.
+///
+/// On
+///    * linux this function simply returns `fun(dbService)`
+///
+///    * macos this function makes a new service scope, optionally builds an
+///      apiary datastore and registers an apiary datastore in the new service
+///      scope
+///
+Future withCorrectDatastore(Future fun(DatastoreDB db), DatastoreDB savedDb) {
+  if (Platform.isMacOS) {
+    return fork(() async {
+      registerDbService(savedDb ?? await initializeApiaryDatastore());
+      return fun(dbService);
+    });
+  } else {
+    assert(dbService != null);
+    return fun(dbService);
+  }
+}