add modal component example

Author: yyx990803

source/examples/hackernews.md

@@ -1,6 +1,6 @@
 title: HackerNews Clone
 type: examples
-order: 8
+order: 9
 ---
 
 > This is a HackerNews clone built upon HN's official Firebase API, and using Webpack + vue-loader for the build setup.
@@ -9,4 +9,4 @@ order: 8
   <a href="http://vuejs.github.io/vue-hackernews" target="_blank"><img style="width:100%" src="/images/hn.png"></a>
 </div>
 
-> [[Source](https://github.com/yyx990803/vue-hackernews)]
+> [[Source](https://github.com/yyx990803/vue-hackernews)]

source/examples/modal.md

@@ -0,0 +1,9 @@
+title: Modal Component
+type: examples
+order: 7
+is_new: true
+---
+
+> Features used: component, prop passing, content insertion, transitions.
+
+<iframe width="100%" height="500" src="http://jsfiddle.net/yyx990803/bfzpwxo4/embedded/result,html,js,css" allowfullscreen="allowfullscreen" frameborder="0"></iframe>

source/examples/todomvc.md

@@ -1,6 +1,6 @@
 title: TodoMVC
 type: examples
-order: 7
+order: 8
 ---
 
 > This is a fully spec-compliant TodoMVC implementation in under 120 effective lines of JavaScript (excluding comments and blank lines).