code: func JoinOnJSONField(jsonField, foreignCol string) string {
  	return fmt.Sprintf(`%[1]s @> concat('{"%[2]s": "', %[3]s, '"}')::jsonb`, Column(WorkItemStorage{}.TableName(), "fields"), jsonField, foreignCol)
  }
docs: // JoinOnJSONField returns the ON part of an SQL JOIN for the given fields