Adding missing meta keywords tag

_config.yml

@@ -3,6 +3,7 @@ title: Freelancer
 email: your-email@domain.com
 url: https://example.github.io
 description: "Write an awesome description for your new site here. You can edit this line in _config.yml. It will appear in your document head meta (for Google search results) and in your feed.xml site description."
+keywords: "your keywords, separated by commas"
 skills: "Web Developer - Graphic Artist - User Experience Designer"
 meta_author: LastName FirstName
 

_includes/head.html

@@ -4,6 +4,7 @@
     <title>{% if page.title %}{{ page.title }}{% else %}{{ site.title }}{% endif %}</title>
     <meta name="viewport" content="width=device-width">
     <meta name="description" content="{{ site.description }}">
+    <meta name="keywords" content="{{ site.keywords }}" />
     {% if site.meta_author %}<meta name="author" content="{{ site.meta_author }}">{% endif %}
     <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.url }}">
     <link rel="alternate" type="application/rss+xml" title="RSS" href="/feed.xml">