Update README.md (#120)

- Add `server.start` to hapi example.
- Lowercase hapi

README.md

@@ -84,6 +84,13 @@ server.register({
     options: { schema: myGraphQLSchema },
     routes: { prefix: '/graphql' },
 });
+
+server.start((err) => {
+    if (err) {
+        throw err;
+    }
+    console.log(`Server running at: ${server.info.uri}`);
+});
 ```
 ### Koa
 ```js