getting-started-rails.asciidoc in elastic-apm-2.2.0

- old
+ new

@@ -1,4 +1,10 @@
+ifdef::env-github[]
+NOTE: For the best reading experience,
+please view this documentation at
+https://www.elastic.co/guide/en/apm/agent/ruby/current/introduction.html[elastic.co]
+endif::[]
+
 [[getting-started-rails]]
 == Getting started with Rails
 
 [float]
 === Setup