upgrade example to actix-web 0.7

web-cors/backend/src/main.rs

@@ -8,7 +8,10 @@ extern crate serde;
 extern crate serde_json;
 
 use actix_web::{
-    http::{header, Method}, middleware, middleware::cors::Cors, server, App,
+    http::{header, Method},
+    middleware,
+    middleware::cors::Cors,
+    server, App,
 };
 use std::env;