autoload older notifications when scrolled to the bottom

src/components/mobile_nav/mobile_nav.js

@@ -63,6 +63,11 @@ const MobileNav = {
     },
     markNotificationsAsSeen () {
       this.$refs.notifications.markAsSeen()
+    },
+    onScroll ({ target: { scrollTop, clientHeight, scrollHeight } }) {
+      if (this.$store.state.config.autoLoad && scrollTop + clientHeight >= scrollHeight) {
+        this.$refs.notifications.fetchOlderNotifications()
+      }
     }
   },
   watch: {