title: Add row in one table for every nth entry in another table
body: <p>Basically what I have is a system where users get rewarded for every 10 comments. So, in the db, one table captures the comments, and the other a reward for every 10th comment added. For instance, if a user has added 40 comments, they will have 4 rewards/4 rows in table 2.</p>
  
  <p>It sounds so simple to me, but I can't seem to figure it. Thought maybe a modulus operator in there could help, but i need to add a new row in table 2 each time, not overwrite, or rewrite the rows each time.</p>
  
  <p>Help appreciated; I've a feeling it's right in front of me!</p>