Merge pull request #740 from Ilshidur/patch-1

Update Keymetrics description

README.md

@@ -224,7 +224,7 @@ Table of Contents
   * [thousandeyes.com](https://www.thousandeyes.com/) — Network and user experience monitoring. 3 locations and 20 data feeds of major web services free
   * [datadoghq.com](https://www.datadoghq.com/) — Free for up to 5 nodes
   * [stackdriver.com](http://www.stackdriver.com/) — Free monitoring up to 10 servers/hosted services
-  * [keymetrics.io](https://keymetrics.io/) — Free for 2 servers with 7 days data retention
+  * [keymetrics.io](https://keymetrics.io/) — Free for 2 servers and 1 user
   * [newrelic.com](https://newrelic.com/) — Free with 24 hours data retention
   * [nodequery.com](https://nodequery.com/) — Free basic server monitor up to 10 servers
   * [watchsumo.com](http://www.watchsumo.com/) — Free website monitoring, 50 http(s), Ping or keywords, every 5+ minutes