Fix broken twitter link. Fixes
@@ -55,7 +55,7 @@ classes: demo_summary
.demo-summary--item
h4 Enjoying Habitat so far? We appreciate you helping us spread the word.
- a.social-icon.twitter href="twitter.com/habitatsh" target="_blank": img src="/images/icons/icon-twitter.svg"
+ a.social-icon.twitter href="https://twitter.com/habitatsh" target="_blank": img src="/images/icons/icon-twitter.svg"
/ a.social-icon.facebook href=""
.row.collapse
.columns.large-12
