Add site image for Twitter card

And a proper title on the home page.

config.toml

@@ -53,6 +53,9 @@ twitter = "GoHugoIO"
   ## Google Tag Manager
   gtmid = ""
 
+  # First one is picked as the Twitter card image if not set on page.
+  images = ["images/gohugoio-card.png"]
+
   flex_box_interior_classes = "flex-auto w-100 w-40-l mr3 mb3 bg-white ba b--moon-gray nested-copy-line-height"
 
   #sidebar_direction = "sidebar_left"

content/_index.md

@@ -1,5 +1,5 @@
 ---
-title: "Hugo"
+title: "Hugo: A Fast and Flexible Website Generator"
 date: 2017-03-02T12:00:00-05:00
 features:
   - heading: Blistering Speed