(fix) improve example test slack alert

docs/my-website/docs/proxy/budget_alerts.md

@@ -0,0 +1,20 @@
+import Image from '@theme/IdealImage';
+
+# 🚨 Budget Alerting
+
+**Alerts when a project will exceed it’s planned limit**
+
+<Image img={require('../../img/budget_alert.png')} />
+
+## Quick Start
+
+### 1. Setup Slack Alerting on your Proxy Config.yaml 
+
+
+### 1. Create API Key on Admin UI
+- Set a key name 
+- Set a Soft Budget on when to get alerted 
+
+### 2. Test Alerting
+
+### 3. Check Slack