I think we should be able to assign multiple builders on one building
suppose you want to upgrade 1 gold mine.
24h time for the upgrade
and assigning 2 builders on one of the gold mine will result in it decreasing by 6 hours which makes 18 hours, it would help in the situations which you do not have the gold or elixir to upgrade and you have a free builder laying around.
please reply and find loopholes or disadvantages. i think this is a good idea

