Merge branch 'ci-scala-example' into 'master'

Ci scala example

## What does this MR do?

Add a scala CI example.

## Why was this MR needed?

Supersedes https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2984

See merge request !4774

doc/ci/examples/README.md

@@ -4,7 +4,8 @@
 - [Test and deploy a Ruby application to Heroku](test-and-deploy-ruby-application-to-heroku.md)
 - [Test and deploy a Python application to Heroku](test-and-deploy-python-application-to-heroku.md)
 - [Test a Clojure application](test-clojure-application.md)
-- [Using `dpl` as deployment tool](../deployment/README.md)
+- [Test a Scala application](test-scala-application.md)
+- [Using `dpl` as deployment tool](deployment/README.md)
 - Help your favorite programming language and GitLab by sending a merge request
   with a guide for that language.
 

doc/ci/examples/test-scala-application.md

+## Test a Scala application
+
+This example demonstrates the integration of Gitlab CI with Scala
+applications using SBT. Checkout the example
+[project](https://gitlab.com/gitlab-examples/scala-sbt) and
+[build status](https://gitlab.com/gitlab-examples/scala-sbt/builds).
+
+### Add `.gitlab-ci.yml` file to project
+
+The following `.gitlab-ci.yml` should be added in the root of your
+repository to trigger CI:
+
+``` yaml
+image: java:8
+
+before_script:
+  - apt-get update -y
+  - apt-get install apt-transport-https -y
+  # Install SBT
+  - echo "deb http://dl.bintray.com/sbt/debian /" | tee -a /etc/apt/sources.list.d/sbt.list
+  - apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 642AC823
+  - apt-get update -y
+  - apt-get install sbt -y
+  - sbt sbt-version
+
+test:
+  script:
+    - sbt clean coverage test coverageReport
+```
+
+The `before_script` installs [SBT](http://www.scala-sbt.org/) and
+displays the version that is being used. The `test` stage executes SBT
+to compile and test the project.
+[scoverage](https://github.com/scoverage/sbt-scoverage) is used as an SBT
+plugin to measure test coverage.
+
+You can use other versions of Scala and SBT by defining them in
+`build.sbt`.
+
+### Display test coverage in build
+
+Add the `Coverage was \[\d+.\d+\%\]` regular expression in the
+**Settings > Edit Project > Test coverage parsing** project setting to
+retrieve the test coverage rate from the build trace and have it
+displayed with your builds.
+
+**Builds** must be enabled for this option to appear.