Let's say the follow chain of events occur:
- User posts an answer to a question without tag
- User gets some upvotes (let's say 3) to the answer.
- Post gets marked with tag
- User gets more upvotes (say 2 more).
For purposes of the tag badge calculation, does the user get 2 points, or 5?
While we're on the topic, if someone downvotes you, do you lose a vote on the tag?