added traits exercises

exercises/traits/traits2.rs

@@ -0,0 +1,35 @@
+// 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! Hints at the bottom.
+
+// I AM NOT DONE
+
+trait AppendBar {
+    fn append_bar(self) -> Self;
+}
+
+//TODO: Add your code here
+
+
+
+
+#[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"));
+    }
+
+}