Currently, arbitrator uses a hashing algorithm based on a number of items that (presumably) make the game unique. Unfortunately, some of these things make the game too unique. For example, games that are rescheduled are sometimes thought by arbitrator to be different games, even though the game id and group is the same.

We should change these hashes in the following way:

• Hashes should be reversible (right now they are just a SHA1 hash, and we need to be able to extract the game id and group name from the hashed data, similar to how JWT works).
• Hashes should be based on ONLY the game id and group name.