Show random games on the home page

[marein]

Show 5-10 running games on the home page.

• Each game is updated in realtime.
• Each game can be replaced by another random game with a renew button.
• With a global renew button, all games can be renewed with a new set of random games.
• A game always remains on the screen, even if it is finished (unless a renew button is clicked).
• By clicking on a game, the user is redirected to the game page.

Possible implementation

• Use srandmember to display x random games.
• Use a zset to display the x most recently created games.
• Use a zset to display games of the highest rated players. Implement Elo rating #28 would be a prerequisite for this solution.