Add YouTube social link

config.toml

@@ -13,4 +13,5 @@ paths = "safe"  # Preserve capitalization
 github_url = "https://github.com/WorldWideTelescope/wwt-user-website"
 twitter_url = "https://twitter.com/wwtelescope"
 facebook_url = "https://facebook.com/wwtelescope"
+youtube_url = "https://www.youtube.com/c/AASWorldWideTelescope"
 google_analytics_id = "UA-107473046-1"

templates/base.html

@@ -98,6 +98,10 @@
             <i class="fa fa-github"></i>
           </a>
 
+          <a class="footer-icon" href="{{config.extra.youtube_url | safe}}" title="YouTube channel" aria-label="YouTube channel">
+            <i class="fa fa-youtube-square"></i>
+          </a>
+
           <a class="footer-icon" href="{{config.extra.facebook_url | safe}}" title="Facebook" aria-label="Facebook">
             <i class="fa fa-facebook"></i>
           </a>