Update Exercises Directory Names to Reflect Order

exercises/09_strings/strings2.rs

@@ -0,0 +1,21 @@
+// strings2.rs
+//
+// Make me compile without changing the function signature!
+//
+// Execute `rustlings hint strings2` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+fn main() {
+    let word = String::from("green"); // Try not changing this line :)
+    if is_a_color_word(word) {
+        println!("That is a color word I know!");
+    } else {
+        println!("That is not a color word I know.");
+    }
+}
+
+fn is_a_color_word(attempt: &str) -> bool {
+    attempt == "green" || attempt == "blue" || attempt == "red"
+}