Handle whitelist configuration before active_record.set_configs
Handle whitelist configuration before active_record.set_configs

Add an initializer block that runs before the active_record.set_configs
initializer so that Active Record doesn't blow up trying to set the
whitelist_attributes configuration variable.

Closes #5

rails/protected_attributes,gauthier-delacroix/protected_attributes,globalxolutions/protected_attributes,westonganger/protected_attributes_continued