Fix fontforge#76 fontforge#72 added open graph data and twitter card.

_config.yml

@@ -7,3 +7,7 @@ plugins:
 include:
   - _images
   - _static
+socialTitle: FontForge
+socialDescription: FontForge is a free and open-source outline font editor.
+socialImage: /assets/img/social-banner.png
+socialAuthor: '@fontforge'

_includes/html-start.html

@@ -5,10 +5,26 @@
   <meta charset="utf-8">
   <title>{{ page.title }}</title>
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <meta name="description" content="FontForge is free and open-source outline font editor.">
+  <meta name="description" content="{{ site.socialDescription }}" />
   <meta name="author" content="The FontForge Project Contributors">
   <meta name="keywords" content="FontForge,font,typeface,design,create,opentype,truetype,UFO,SFD">
 
+  <!-- Twitter Card data -->
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:site" content="{{ site.socialAuthor }}">
+  <meta name="twitter:title" content="{{ site.socialTitle }}">
+  <meta name="twitter:description" content="{{ site.socialDescription }}">
+  <meta name="twitter:creator" content="{{ site.socialAuthor }}">
+  <meta name="twitter:image" content="{{ site.socialImage }}">
+
+  <!-- Open Graph data -->
+  <meta property="og:title" content="{{ site.socialTitle }}" />
+  <meta property="og:type" content="website" />
+  <meta property="og:url" content="{{ site.url }}" />
+  <meta property="og:image" content="{{ site.socialImage }}" />
+  <meta property="og:description" content="{{ site.socialDescription }}" />
+  <meta property="og:site_name" content="{{ site.socialTitle }}" />
+
   <!-- CSS -->
   <link href='https://fonts.googleapis.com/css?family=Merriweather:400,700' rel='stylesheet' type='text/css'>
   <link href="/assets/css/bootstrap.css" rel="stylesheet">