fix gcd logic (i want to sleep :(( )

Author: yng-trouble

brain_games/games/b_gcd_logic.py

@@ -24,7 +24,7 @@ def b_gcd():
             rem = a % b
             a = b
             b = rem
-        if b != 0:
+        if b == 0:
             gcd = a
         if answer == str(gcd):
             print('Correct!')