Add specific bug reporting guidelines to contributing.md. [ci skip]

Add boldface and bullets to make more readable.

Make sentences declarative.

Remove "you"s.

CONTRIBUTING.md

-Ruby on Rails is a volunteer effort. We encourage you to pitch in. [Join the team](http://contributors.rubyonrails.org)!
+## How to contribute to Ruby on Rails
 
-* If you want to submit a bug report please make sure to follow our [reporting guidelines](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#reporting-an-issue).
+#### **Did you find a bug?**
 
-* If you want to submit a patch, please read the [Contributing to Ruby on Rails](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html) guide.
+* **Ensure the bug was not already reported** by searching on GitHub under [Issues](https://github.com/rails/rails/issues).
 
-* If you want to contribute to Rails documentation, please read the [Contributing to the Rails Documentation](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation) section of the aforementioned guide.
+* If unable to find an open issue addressing the problem, [open a new one](https://github.com/rails/rails/issues/new). Be sure to include a **title and clear description**, as much relevant information as possible, and a **code sample** or an **executable test case** demonstrating the expected behavior that is not occurring.
 
-*We only accept bug reports and pull requests on GitHub*.
+* If possible, use the relevant bug report templates to create the issue. Simply copy the content of the appropriate template into a .rb file, make the necessary changes to demonstrate the issue, and **paste the content into the issue description**:
+  * [**Active Record** (models, database) issues](https://github.com/rails/rails/blob/master/guides/bug_report_templates/active_record_master.rb)
+  * [**Action Pack** (controllers, routing) issues](https://github.com/rails/rails/blob/master/guides/bug_report_templates/action_controller_master.rb)
+  * [**Generic template** for other issues](https://github.com/rails/rails/blob/master/guides/bug_report_templates/generic_master.rb)
 
-* If you have a question about how to use Ruby on Rails, please [ask it on the rubyonrails-talk mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-talk).
+* For more detailed information on submitting a bug report and creating an issue, visit our [reporting guidelines](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#reporting-an-issue).
 
-* If you have a change or new feature in mind, please [suggest it on the rubyonrails-core mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core) and start writing code.
+#### **Did you write a patch that fixes a bug?**
+
+* Open a new GitHub pull request with the patch.
+
+* Ensure the PR description clearly describes the problem and solution. Include the relevant issue number if applicable.
+
+* Before submitting, please read the [Contributing to Ruby on Rails](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html) guide to know more about coding conventions and benchmarks.
+
+#### **Do you intend to add a new feature or change an existing one?**
+
+* Suggest your change in the [rubyonrails-core mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core) and start writing code.
+
+* Do not open an issue on GitHub until you have collected positive feedback about the change. GitHub issues are primarily intended for bug reports and fixes.
+
+#### **Do you have questions about the source code?**
+
+* Ask any question about how to use Ruby on Rails in the [rubyonrails-talk mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-talk).
+
+#### **Do you want to contribute to the Rails documentation?**
+
+* Please read [Contributing to the Rails Documentation](http://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation).
+
+</br>
+Ruby on Rails is a volunteer effort. We encourage you to pitch in and [join the team](http://contributors.rubyonrails.org)!
 
 Thanks! :heart: :heart: :heart: