Add Caddy mixin (grafana#424)

* Add Caddy mixin

* Fix lint

* Remove unecessary space

* Add extra line at the end

README.md

@@ -17,6 +17,9 @@ This repository contains various Jsonnet libraries we use at Grafana Labs:
 * [`nodejs-mixin`](nodejs-mixin/): A set of reusable and extensible dashboards
   for Node.js.
 
+* [`caddy-mixin`](caddy-mixin/): A set of reusable and extensible dashboards
+  for Caddy.
+
 * [`oauth2-proxy`](oauth2-proxy/): A jsonnet configuration for deploying bitly's
   OAuth proxy to Kubernetes.
 

caddy-mixin/README.md

@@ -0,0 +1,21 @@
+# Caddy Mixin
+
+The Caddy Mixin is a set of configurable, reusable, and extensible 
+dashboards.
+
+To use them, you need to have `mixtool` and `jsonnetfmt` installed. If you
+have a working Go development environment, it's easiest to run the following:
+```bash
+$ go get github.com/monitoring-mixins/mixtool/cmd/mixtool
+$ go get github.com/google/go-jsonnet/cmd/jsonnetfmt
+```
+
+You can then build the Prometheus rules files `alerts.yaml` and
+`rules.yaml` and a directory `dashboard_out` with the JSON dashboard files
+for Grafana:
+```bash
+$ make build
+```
+
+For more advanced uses of mixins, see
+https://github.com/monitoring-mixins/docs.