title: Storing credits in database
body: <p>Just a quickey. I am developming website, where you can buy credits and spend them later for things on the website. 
  My question is, is it ok to store amount of credits with user (user table, column credits and iteger amount) or it is necessary (or just better) to have separate table with user id and amount ?</p>
  
  <p>Thanks</p>