upd readme

README.md

@@ -1,13 +1,14 @@
 # tsdb-kit
 
-[![Build Status](https://travis-ci.org/CorpGlory/tsdb-kit.svg?branch=master)](https://travis-ci.org/CorpGlory/tsdb-kit)
+Node.js library and CLI-tool for querying timeseries-datasources from backend directly or using Grafana as proxy.
 
-Node.js library and utilities for running Grafana datasources on backend.
-You can send your datasource metrics from Grafana to compile it on Node.js and query your datasource via Grafana API in background.
+User gets a unified interface to all datasources. Library gives single output format: fields order, time units, etc.
 
-User gets a unified interface to all datasources. Library gives single output format: fields order, time units, etc
+## Supported direct datasources
 
-## Supported datasources
+* Prometheus
+
+## Supported Grafana datasources
 
 * Influxdb
 * Graphite
@@ -15,7 +16,15 @@ User gets a unified interface to all datasources. Library gives single output fo
 * PostgreSQL / TimescaleDB / MySQL
 * ElasticSearch
 
-Please write us at ping@corpglory.com if you want your datasource to be supported: 
+Please write us at ping@corpglory.com if you want your datasource to be supported
+
+## CLI usage
+
+For now, CLI supports only direct Prometheus queries without auth
+
+Example:
+
+`npx tsdb-kit -u http://localhost:9090 -q '100-(avg by (instance) (irate(node_cpu_seconds_total{mode="idle"}[5m])) * 100)'`
 
 ## Projects based on library
 * [grafana-data-exporter](https://github.com/CorpGlory/grafana-data-exporter)