Add support button

Author: choldgraf

doc/_static/custom.css

@@ -3,6 +3,13 @@
     --sd-color-secondary: #f5a252;    
 }
 
+/* Header */
+i.fa.fa-heart {
+    color: #e66783;
+}
+
+/* Text elements */
+
 div.body p.caption {
     font-size: 1.2em;
 }

doc/conf.py

@@ -91,6 +91,13 @@
     "google_analytics_id": "UA-101904940-3",
     "github_url": "https://github.com/jupyterhub/binder",
     "twitter_url": "https://twitter.com/mybinderteam",
+    "icon_links": [
+        {
+            "name": "Support",
+            "url": "https://mybinder.readthedocs.io/en/latest/about/support.html",
+            "icon": "fa fa-heart",
+        }
+   ]
 }
 
 html_context = {