Rewrite wiki page with react (#2258)

frontend/src/components/search.js

@@ -0,0 +1,19 @@
+import React, { Component } from 'react';
+import { repoID, siteRoot } from './constance';
+
+class Search extends Component {
+  render() {
+    return (
+      <form id="top-search-form" method="get" action={siteRoot + 'search/'} className="hidden-sm-down search-form">
+        <input
+          type="text" className="search-input" name="q"
+          placeholder="Search files in this wiki"
+        />
+        <input type="hidden" name="search_repo" value={repoID} />
+        <button type="submit" className="search-submit" aria-label="Submit"><span className="icon-search"></span></button>
+      </form>
+    )
+  }
+}
+
+export default Search;