Add twitter metadata

- copied again from masonstrap

Closes #55

go/go/templates/layouts/base.html

@@ -29,6 +29,14 @@
     <meta property="og:site_name" content="SRCT Go">
     <meta property="og:locale" content="en_US">
     <meta property="article:author" content="SRCT">
+    <!-- Twitter card tags -->
+    <meta name="twitter:card" content="summary">
+    <meta name="twitter:site" content="@MasonSRCT">
+    <meta name="twitter:creator" content="@MasonSRCT">
+    <meta name="twitter:url" content="https://go.gmu.edu/">
+    <meta name="twitter:title" content="SRCT Gp">
+    <meta name="twitter:description" content="University-branded URL shortening.">
+    <!--<meta name="twitter:image" content="https://git.gmu.edu/uploads/project/avatar/10/noun_534670_cc.png">-->
 
     <!-- Load in our icon -->
     <link rel="icon" type="image/ico" href="{% static "img/favicon.ico" %}" />