Add code of conduct to README.md and to contributing guide [ci skip]

README.md

@@ -76,6 +76,8 @@ and may also be used independently outside Rails.
 We encourage you to contribute to Ruby on Rails! Please check out the
 [Contributing to Ruby on Rails guide](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html) for guidelines about how to proceed. [Join us!](http://contributors.rubyonrails.org)
 
+Everyone interacting in Rails and its sub-project’s codebases, issue trackers, chat rooms, and mailing lists is expected to follow the Rails [code of conduct](CODE_OF_CONDUCT.md).
+
 ## Code Status
 
 [![Build Status](https://travis-ci.org/rails/rails.svg?branch=master)](https://travis-ci.org/rails/rails)

guides/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Add code of conduct to contributing guide
+
+    *Jon Moss*
+
 *   New section in Configuring: Configuring Active Job
 
     *Eliot Sykes*

guides/source/contributing_to_ruby_on_rails.md

@@ -15,6 +15,9 @@ After reading this guide, you will know:
 
 Ruby on Rails is not "someone else's framework." Over the years, hundreds of people have contributed to Ruby on Rails ranging from a single character to massive architectural changes or significant documentation - all with the goal of making Ruby on Rails better for everyone. Even if you don't feel up to writing code or documentation yet, there are a variety of other ways that you can contribute, from reporting issues to testing patches.
 
+As mentioned in [Rails
+README](https://github.com/rails/rails/blob/master/README.md), everyone interacting in Rails and its sub-project’s codebases, issue trackers, chat rooms, and mailing lists is expected to follow the Rails [code of conduct](https://github.com/rails/rails/blob/master/CODE_OF_CONDUCT.md).
+
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