add advent of rust day2

Rust/rustifinity/adventofrust/day2.rs

@@ -0,0 +1,10 @@
+pub fn main() {
+    let gift_message = String::from("Merry Christmas! Enjoy your gift!");
+    attach_message_to_present(&gift_message);
+
+    println!("{}", gift_message);
+}
+
+pub fn attach_message_to_present(message: &String) {
+    println!("The present now has this message: {}", message);
+}