"hits" is a reserved field in Joomla that doesn't take much to add. I believe you just need the "hits" field in the database and everything else is automatic since it's a "reserved database name". You can read more on the joomla JTable instruction page docs.joomla.org/Using_the_JTable_class and the JTable API page api.joomla.org/cms-3/classes/JTable.html
(note: I rewrote the JTable instruction page for J3+ from the information I was able to piece together. It's mostly accurate but I don't think anyone with significant Joomla programming experience has reviewed the information.)