Idea: builders currently work singularly on 1 building and that's it. My idea is that you can choose how many builders work on a building in order to speed up the process
EXAMPLE 1:
TH takes 8 days to upgrade
1 builder: 8 days
2 builders: 7 days
3 builders: 6 days
4 builders: 5 days
Or alternatively you use use gems to level up a builders hut, 5 levels and each one speeds it up 10%

