Merge pull request #204 from mauroservienti/meta-keywords-support

meta keywords support

Author: mauroservienti

.gitignore

@@ -1,3 +1,4 @@
 _site
 .sass-cache
-.jekyll-metadata
+.jekyll-metadata
+.jekyll-cache

_includes/head.html

@@ -7,6 +7,20 @@
   <title>{% if page.title %}{{ page.title }}{% else %}{{ site.title }}{% endif %}</title>
   <meta name="description" content="{% if page.excerpt %}{{ page.excerpt | strip_html | strip_newlines | truncate: 160 }}{% else %}{{ site.description }}{% endif %}">
 
+{% assign kw = nil %}
+{% if page.keywords %}
+  {% assign kw = page.keywords %}
+{% else if page.tags %}
+  {% assign kw = page.tags %}
+{% endif %}
+{% if kw %}
+  {% assign kw_string = "" %}
+  {% for k in kw %}
+    {% assign kw_string = kw_string | append: k | append: ', ' %}
+  {% endfor %}
+    <meta name="keywords" content="{{ kw_string }}"/>
+{% endif %}
+
 {% if site.twitter_username %}
   <meta name="twitter:card" content="summary" />
   <meta name="twitter:site" content="@{{ site.twitter_username }}" />