Add boilerplate code for topup notifications

handler/notify.py

@@ -43,3 +43,6 @@ class Notify(object):
 
     def notify_withdrawal(self, amount_usd):
         self.sendmsg(f"Total: {amount_usd}", title="Withdrawal", tags="profit")
+
+    def notify_need_topup(self, amount_usd_xmr, amount_usd_btc):
+        self.sendmsg(f"XMR: {amount_usd_xmr} | BTC: {amount_usd_btc}", title="Topup needed", tags="admin")