Merge pull request #135 from librato/chore/note-re-tags

note about tags support

README.md

@@ -5,6 +5,12 @@ Librato Metrics
 
 A convenient Ruby wrapper for the Librato Metrics API.
 
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+**NOTE:** Starting with version 2.1.0 librato-metrics requires a Librato account that [supports tagged metrics](https://www.librato.com/docs/kb/faq/account_questions/tags_or_sources/). If your Librato account doesn't yet support tagged metrics please use the [1.6.1 version](https://rubygems.org/gems/librato-metrics/versions/1.6.1).
+
+---
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 This gem provides granular control for scripting interactions with the Metrics core API. It is well suited for integrations, scripts, workers & background jobs. If you want to submit from a web app, take at look at [librato-rails](https://github.com/librato/librato-rails) and/or [librato-rack](https://github.com/librato/librato-rack).
 
 ## Installation