add search box to feed list page

feedlist.html

@@ -107,6 +107,20 @@
 {% raw %}
 
 <div id="main-post" class="post">
+  <form id="search-form-inline" target="_blank" action="/search.html" method="get">
+    <label for="search-box-inline"></label>
+    <input type="text" class="github-search-box" id="search-box-inline" name="query" placeholder="search">
+  </form>
+
+  <script>
+  document.getElementById('search-form-inline').addEventListener('submit', function(e){
+    e.preventDefault();
+    var value_search = document.getElementById('search-box-inline').value;
+    setTimeout(function(){
+        document.location = "https://github.com/rweekly/rweekly.org/search?utf8=%E2%9C%93&q=" + encodeURIComponent(value_search) + "+extension%3Ar+extension%3Amd&type=Code";
+    }, 250);
+  });
+  </script>
 
   <div id="latest-app" class="inner-app-hide">
     <h3>R Weekly Live Feed List</h3>