day 12 part 1

src/main.rs

@@ -16,6 +16,7 @@ fn main() {
         (9, day09::day_main),
         (10, day10::day_main),
         (11, day11::day_main),
+        (12, day12::day_main),
         // PLACEHOLDER
     ]);
     let day: Option<u8> = args().nth(1).and_then(|a| a.parse().ok());