The first thing we needed here was an enum rather than a boolean to determine how a directory_column was created. Now we have
plugin directory columns.
This plugin API is assuming that the plugin has added a migration to a column to the
This was created to be initially used by discourse-solved. PR with API usage - Use `add_directory_column` API to add solutions count to user directory by markvanlan · Pull Request #137 · discourse/discourse-solved · GitHub