added template for AOC.

src/template/part2.rs

@@ -0,0 +1,13 @@
+pub fn part2() -> usize {
+    return 0;
+}
+
+#[cfg(test)]
+mod day01 {
+    use super::*;
+
+    #[test]
+    fn test_part2() {
+        assert_eq!(part2(), 0);
+    }
+}