Merge branch 'hotfix/36'

Close #36
[#38] addIdentifiers instead of setIdentifiers

- Since `setEventManager()` is called after we've already set our
  service-specific identifiers in the `Resource`'s event manager
  instance, we need to instead call `addIdentifiers()` to ensure we do
  not overwrite them.
Merge branch 'hotfix/38' into develop

Forward port #38