New spell

Invisible spell
it will make the invisible the troops so the defenses cannot attack them but the trrops can destroy the defenses while in the ring. (unlocks at : Th9)

cost:- lvl 1: 80 dark elixir
lvl 2: 120 dark elixir
lvl 3: 150 dark elixir

level : Upto 3
duration :- lvl 1 : 6 seconds
lvl 2 : 8 seconds
lvl 3 : 10 seconds

brewing time: 40 minutes

upgrading time :- lvl 1: 6 days
lvl 2 : 8 days
lvl 3 : 10 days
upgrading requirements :- lvl 1 : 20000 dark elixir
lvl 2: 50000 dark elixir
lvl 3: 100000 dark elixir