tx_news_domain_model_news
is the correct table, but adding the data there is not sufficient for TYPO3. You also need to add that data to the TCA
(Table configuration array) and to the Database definition, and make EXT:news aware of the new field
The most simple way to do so is this:
- Create a new Extension using the "extension_builder"-Extension (creates the mentioned entries in the TCA and the database definition files)
- Create a class "Tx__Domain_Model_News" in your new extension that contains the new fields and setters + getters for them (Use the naming conventions, otherwise it won't work!)
- Add a file "Resources/Private/extend-news.txt" to your new extension, containing "Domain/Model/News" as its only content.
That should be it. Here is a link to the extension manual, describing the process:
http://docs.typo3.org/typo3cms/extensions/news/Main/Tutorial/ExtendingNews/Index.html