add support of meta keywords

_layouts/default.html

@@ -4,8 +4,9 @@
     <meta charset="utf-8">
     <meta http-equiv="X-UA-Compatible" content="chrome=1">
     <title>{{ page.title }}</title>
-    <meta name="author" content="Unknown" >
+    <meta name="author" content="Evgeniy Alekseev">
     <meta name="description" content="arcanis' homepage">
+    <meta name="keywords" content="{{ page.tags }}">
     <link href="/authors" rel="license" type="text/html">
 
     <link href="/resources/css/styles.css" rel="stylesheet" type="text/css">