feat(mailhog): IPCEICIS-3048 - added documentation

template/stacks/ref-implementation/mailhog/README.md

@@ -0,0 +1,54 @@
+# Mailhog
+
+[MailHog is an email testing tool for developers](https://github.com/mailhog/MailHog).
+
+## In cluster SMTP service
+
+Ypu can send ESMTP emails in the cluster to `mailhog.mailhog.svc.cluster.local`, standard port `1025`, as defined in the service manifest:
+
+```yaml
+apiVersion: v1
+kind: Service
+metadata:
+  name: mailhog
+spec:
+  ports:
+    - name: smtp
+      port: 1025
+```
+
+## Ingress
+
+Mailhog offers both WebUi and API at `https://{{{ .Env.DOMAIN }}}/mailhog`.
+
+The ingress definition is in `stacks/core/ingress-apps/mailhog.yaml` (BTW, why isn't this ingress file here in this folder ??) routing to the mailhog' service
+
+```yaml
+spec:
+  rules:
+  - host: {{{ .Env.DOMAIN }}}
+    http:
+      paths:
+      - backend:
+        ...
+        path: /mailhog
+```
+
+## API
+
+For usage of the API see https://github.com/mailhog/MailHog/blob/master/docs/APIv2.md
+
+## Tests
+
+```bash
+kubectl run busybox --rm -it --image=busybox -- /bin/sh
+
+# inside bsybox
+wget -O- http://mailhog.mailhog.svc.cluster.local:8025/mailhog
+
+# check smtp port
+nc -zv mailhog.mailhog.svc.cluster.local 1025
+
+# send esmtp, first install swaks
+swaks --to test@example.com --from test@example.com --server mailhog:1025 --data "Subject: Test-Mail\n\nDies ist eine Test-Mail."
+```