Error: PG::UndefinedColumn. Custom field not creating column

Thanks–I was starting to figure something like that must be going on. So perhaps I’d need to do a join with that model (really having to dust off my rails here). I’ve tried something like this:

Topic.joins(:topic_custom_field).where(fun_level: 'super-duper-fun') }

but I get the error: ActiveRecord::ConfigurationError (Can't join 'Topic' to association named 'topic_custom_field'; perhaps you misspelled it?)

Any ideas on the right syntax?