How can I add records to a master table that is not in a collection?

I am trying to use a table to record a situation for a logged user (he/she wont be able to participate in a particular activity). This table is a master table with no relation to any other, so I can´t use newCollectionItem.

I did not find any alternative. I expected something like addRecord("Entity"), returning the ID of the record added.

What can I do ? I would not like to create a WebService for such a trivial task.