docs: add README

Signed-off-by: Lorenz Herzberger <[email protected]>

README.md

@@ -0,0 +1,19 @@
+# rddl-prometheus-exporter
+This service is responsible for providing vital network metrics for prometheus.
+
+## Execution
+The service can be executed via the following go command without having it previously built:
+```
+go run cmd/rddl-prometheus-exporter/main.go
+```
+
+## Configuration
+The service needs to be configured via the ```./app.toml``` file or environment variables. The defaults are:
+```
+rpc-host = 'localhost:18884' // elementsd rpc host
+rpc-pass = 'password'        // elementsd rpc password
+rpc-user = 'user'            // elementsd rpc user
+service-bind = 'localhost'
+service-port = 8080
+wallets = 'wallet1,wallet2'  // liquid wallets
+```