Add documentation to setup error reporting

SUMMARY.md

@@ -27,6 +27,7 @@
     * [Kubernetes Dashboard](deployment/digital-ocean/dashboard/README.md)
     * [HTTPS](deployment/digital-ocean/https/README.md)
   * [Human Connection](deployment/human-connection/README.md)
+    * [Error Reporting](deployment/human-connection/error-reporting/README.md)
     * [Mailserver](deployment/human-connection/mailserver/README.md)
     * [Maintenance](deployment/human-connection/maintenance/README.md)
   * [Volumes](deployment/volumes/README.md)

deployment/human-connection/error-reporting/README.md

@@ -0,0 +1,16 @@
+# Error reporting
+
+We use [Sentry](https://github.com/getsentry/sentry) for error reporting in both
+our backend and web frontend. You can either use a hosted or a self-hosted
+instance. Just set the two `DSN` in your
+[configmap](../templates/configmap.template.yaml) and update the `COMMIT`
+during a deployment with your commit or the version of your release.
+
+## Self-hosted Sentry
+
+For data privacy it is recommended to set up your own instance of sentry. 
+If you are lucky enough to have a kubernetes cluster with the required hardware
+support, try this [helm chart](https://github.com/helm/charts/tree/master/stable/sentry).
+
+On our kubernetes cluster we get "mult-attach" errors for persistent volumes.
+Apparently Digital Ocean's kubernetes clusters do not fulfill the requirements.