Link to review apps example from docs

[ci skip]

doc/ci/examples/README.md

@@ -13,6 +13,7 @@ Apart from those, here is an collection of tutorials and guides on setting up yo
 - [Test a Scala application](test-scala-application.md)
 - [Test a Phoenix application](test-phoenix-application.md)
 - [Using `dpl` as deployment tool](deployment/README.md)
+- [Example project that shows how to use Review Apps](https://gitlab.com/gitlab-examples/review-apps-nginx/)
 - [Blog post about using GitLab CI for iOS projects](https://about.gitlab.com/2016/03/10/setting-up-gitlab-ci-for-ios-projects/)
 - [Repositories with examples for various languages](https://gitlab.com/groups/gitlab-examples)
 - [The .gitlab-ci.yml file for GitLab itself](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/.gitlab-ci.yml)

doc/ci/yaml/README.md

@@ -594,6 +594,8 @@ create the `review-apps/branch-name` environment.
 
 This environment should be accessible under `https://branch-name.review.example.com/`.
 
+You can see a simple example at https://gitlab.com/gitlab-examples/review-apps-nginx/.
+
 ### artifacts
 
 >**Notes:**