Fix a missing link and create a separate "Testing guides" section

Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/development/README.md

@@ -22,7 +22,6 @@
 
 ## Backend guides
 
-- [Testing standards and style guidelines](testing_guide/index.md)
 - [API styleguide](api_styleguide.md) Use this styleguide if you are
   contributing to the API.
 - [Sidekiq guidelines](sidekiq_style_guide.md) for working with Sidekiq workers
@@ -71,6 +70,11 @@
 - [Hash indexes](hash_indexes.md)
 - [Swapping Tables](swapping_tables.md)
 
+## Testing guides
+
+- [Testing standards and style guidelines](testing_guide/index.md)
+- [Frontend testing standards and style guidelines](testing_guide/frontend_testing.md)
+
 ## Documentation guides
 
 - [Documentation styleguide](doc_styleguide.md): Use this styleguide if you are

doc/development/testing_guide/index.md

@@ -84,6 +84,7 @@ test should be re-implemented using RSpec instead.
 
 [^1]: /ci/yaml/README.html#dependencies
 
+[rails]: http://rubyonrails.org/
 [RSpec]: https://github.com/rspec/rspec-rails#feature-specs
 [Capybara]: https://github.com/teamcapybara/capybara
 [Karma]: http://karma-runner.github.io/