Swiss-style tournaments

These tournaments are implemented following the advice found about Swiss-style tournaments on chess.com, available at https://support.chess.com/article/758-what-is-a-swiss-tournament :

• * What is a Swiss tournament?

A Swiss tournament is similar to a Round-Robin tournament in that no players are eliminated. Every player will play every round, and the player with the highest number of points at the end of the tournament is the winner.

In a Swiss tournament, however, you don't necessarily play every other player. If there are a lot of players in the tournament, there may not be enough rounds for everyone to play everyone.

In the first round only, high rated players are intentionally paired with low rated players. After the first round, pairings are based on performance: those who won are matched with other winners, losers with losers. There may be some exceptions to avoid color repetition.