title: how do I rollback a database transaction in rails
body: <p>I'm new to rails and have just had my first bad experience with the mighty rails console. I overwrote a column in ALL instead of just one record and after hours of googling I did not find a common way to rollback this stupid transaction (ended up fixing 76 rows manually!).</p>
  
  <p>I was working on the live environment on heroku and just wanted to fix one entry.
  There must be a way to rollback a transaction in the database (postgres) if you did stupid things - not by using pgbackup.</p>
  
  <p>Would be great if you can share some best pratices with me or give me a good reading to start.
  Thanks!</p>