Use same size headers. Add PullReview. Mention shell guide as created by us.

CONTRIBUTING.md

@@ -110,8 +110,7 @@ For examples of feedback on merge requests please look at already [closed merge
 1.  [Rails](https://github.com/bbatsov/rails-style-guide)
 1.  [Testing](https://github.com/thoughtbot/guides/tree/master/style#testing)
 1.  [CoffeeScript](https://github.com/thoughtbot/guides/tree/master/style#coffeescript)
-1.  [Shell commands](doc/development/shell_commands.md)
+1.  [Shell commands](doc/development/shell_commands.md) created by GitLab contributors to enhance security
 1.  [Markdown](http://www.cirosantilli.com/markdown-styleguide)
 
-This is also the style used by linting tools such as [Rubocop](https://github.com/bbatsov/rubocop)
-and [Hound CI](https://houndci.com).
+This is also the style used by linting tools such as [Rubocop](https://github.com/bbatsov/rubocop), PullReview[https://www.pullreview.com/] and [Hound CI](https://houndci.com).

README.md

@@ -83,13 +83,13 @@ or by directly calling the script:
 
 Please login with `root` / `5iveL!fe`.
 
-### Install a development environment
+## Install a development environment
 
 We recommend setting up your development environment with [the cookbook](https://gitlab.com/gitlab-org/cookbook-gitlab/blob/master/README.md#installation). If you do not use the cookbook you might need to copy the example development unicorn configuration file
 
     cp config/unicorn.rb.example.development config/unicorn.rb
 
-### Run in development mode
+## Run in development mode
 
 Start it with [Foreman](https://github.com/ddollar/foreman)