Bukkit

v5.4:

Added ability to customize cooldown time (in minutes)
Added ability to add a fee when a challenger is pulled into the gym and how much the fee is. (Pay for a battle)
Fixed Spamming 2 messages on GymLeader join.
Made it so that if a player disconnects whilst they are in the gym arena, that it won't remove them from the queue. (So you can wait for them if you want)
Added command for player to remove the person from queue if they are offline. (So you can continue with other challengers)

If you remove the player from the queue, they will still have to warp or take them selves out of the gym arena.

There is currently no way to tell if someone has enough balance to pay the fee for the gym. I will look at getting an API for this, for now it just tells you if you receive the money, if you don't then they don't have enough money. And it is up to the gym leaders to make them lose the battle if they want.