Update Exercises Directory Names to Reflect Order

exercises/15_traits/traits2.rs

@@ -0,0 +1,29 @@
+// traits2.rs
+//
+// Your task is to implement the trait `AppendBar` for a vector of strings. To
+// implement this trait, consider for a moment what it means to 'append "Bar"'
+// to a vector of strings.
+//
+// No boiler plate code this time, you can do this!
+//
+// Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+trait AppendBar {
+    fn append_bar(self) -> Self;
+}
+
+// TODO: Implement trait `AppendBar` for a vector of strings.
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn is_vec_pop_eq_bar() {
+        let mut foo = vec![String::from("Foo")].append_bar();
+        assert_eq!(foo.pop().unwrap(), String::from("Bar"));
+        assert_eq!(foo.pop().unwrap(), String::from("Foo"));
+    }
+}