Merge pull request #9 from chatwork/how-to-install-with-helm

Add an instruction to install exporter with helm

README.md

@@ -82,10 +82,26 @@ You can check the metrics by accessing Prometheus ([http://127.0.0.1:9200]()).
 
 ##### Prerequisites
 
-https://github.com/aslafy-z/helm-git
+ - Create a `configmap` to store api key
+ - Install [helm-git](https://github.com/aslafy-z/helm-git) plugin
+
+```
+$ cat configmap.yaml
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: sendgrid-config
+  data:
+    SENDGRID_API_KEY: 'secret'
+$ kubectl apply -f configmap.yaml
+configmap/sendgrid-config created
+```
 
+##### Installing
+
 ```
-$ helm repo add sendgrid-stats-exporter git+https://github.com/chatwork/sendgrid-stats-exporter@charts?ref=v0.0.1
+$ helm repo add sendgrid-stats-exporter 'git+https://github.com/chatwork/sendgrid-stats-exporter@charts?ref=0.0.4'
+$ helm install sendgrid-stats-exporter/sendgrid-stats-exporter --set 'envFrom[0].configMapRef.name=sendgrid-config' --name-template sendgrid-stats-exporter
 ```
 
 ## Building