Also, this relies on the plugin being stored at "custom/apps/plugin" with a urls file in its root directory.  Is `plugin` a string at this point, or an actual object?  We could do something like `plugin.__name__` to refer to its dot path directly (or `plugin.__module__ + '.' + plugin.__name__` or whatever works) or as Cory suggested, define that explicitly in the module's `__init__`.