title: something like same "tag" for multiple commits
body: <p>My dilemma: I always want to mark the last reviewed commit so that I can always specify the diff.
  I let my code to be reviewed only after certain time. How can I remember the last time I had my code reviewed?</p>
  
  <p>My idea was to always tag: "reviewed" the last reviewed commit. However I'd prefer to have the opportunity to tag commits with this as-I-go. Without the need to always delete the tag. +I'd like to remember which diffs I had for reviewing.</p>
  
  <p>So it would be the best if I could tag multiple commits with the same "tag". Unfortunatelly tag is something like an "ID" in DOM. I'd prefer something like  "class" in DOM. Is there something like that?</p>