add backup to index

index.md

@@ -35,6 +35,12 @@ The How-to cards are intended to provide practical guidance in implementing Data
             "icon": "<i class=\"large material-icons\">add_circle</i>",
             "link": "{{ '/cards#contribute' | relative_url }}"
         },
+        {
+            "title": "Backup",
+            "caption": "Guidelines regarding backing up your data",
+            "icon": "<i class=\"large material-icons\">backup</i>",
+            "link": "{{ '/cards#backup' | relative_url }}"
+        },
         {
             "title": "Exchange channels",
             "caption": "I am looking to share data or information",