Global Upgrade System
--Note for upgrades--
Although any players from a team can control structures that provide upgrades, this system still have limitations, one of them is, only 1 player at a time clicking a structure can make the upgrade
second, when clicking an upgrade, the time interval is zero, upgrading the upgrade instantly, but wait, this doesn't mean clicking the upgrade and leaving the structure will still upgrade, no it doesn't continue the upgrade, you need to wait until the upgrade finishes (saying "upgrade completed") then you can leave the structure safely
the upgrade system behaves like this because the system works like, select player 1 red upgrade structure, change upgrade structure owner to owner of selector, if upgrade structure is unselected, it returns back to player 1 red
I need a better system, to fix this problem