add robots + ga account

Author: Houssein Djirdeh

_includes/head.html

@@ -32,6 +32,7 @@
 
   <link rel="stylesheet" href="{{ "/assets/styles/main.css" | relative_url }}">
   <link rel="canonical" href="{{ page.url | replace:'index.html','' | absolute_url }}">
+  <link rel="author" href="https://plus.google.com/109730836902589271473"/>
   <link rel="alternate" type="application/rss+xml" title="{{ site.title | escape }}" href="{{ " /feed.xml
     " | relative_url }}"> {% if jekyll.environment == 'production' and site.google_analytics %} {% include google-analytics.html %} {% endif %}
   <link rel="manifest" href="/assets/manifest.json">

robots.txt

@@ -0,0 +1,6 @@
+---
+layout: null
+---
+
+User-agent: *
+Sitemap: {{ site.url }}/sitemap.xml