Add example for testing clojure application

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

doc/README.md

@@ -14,6 +14,7 @@
 + [Test and deploy Ruby applications to Heroku](examples/test-and-deploy-ruby-application-to-heroku.md)
 + [Test and deploy Python applications to Heroku](examples/test-and-deploy-python-application-to-heroku.md)
++ [Test Clojure applications](examples/test-clojure-application.md)
 + Help your favorite programming language and GitLab by sending a merge request with a guide for that language.
 ### Administrator documentation
@@ -23,4 +24,4 @@
 + [User permissions](permissions/README.md)
 + [Backup/Restore](raketasks/backup_restore.md)
 + [Migrating to packaged CI](migration_to_omnibus/README.md)
-+ [API](api/README.md)
\ No newline at end of file
++ [API](api/README.md)

doc/examples/README.md

@@ -2,3 +2,4 @@
 + [Test and deploy Ruby Application to Heroku](test-and-deploy-ruby-application-to-heroku.md)
 + [Test and deploy Python Application to Heroku](test-and-deploy-python-application-to-heroku.md)
++ [Test Clojure applications](examples/test-clojure-application.md)

doc/examples/test-clojure-application.md

+## Test Clojure applications
+
+This example will guide you how to run tests in your Clojure application.
+
+You can checkout the example [source](https://gitlab.com/dzaporozhets/clojure-web-application) and check [CI status](https://ci.gitlab.com/projects/6306).
+
+### Configure project
+
+This is what the `.gitlab-ci.yml` file looks like for this project:
+
+```yaml
+variables:
+  POSTGRES_DB: sample-test
+  DATABASE_URL: "postgresql://postgres@postgres:5432/sample-test"
+
+before_script:
+  - apt-get update -y
+  - apt-get install default-jre postgresql-client -y
+  - wget https://raw.githubusercontent.com/technomancy/leiningen/stable/bin/lein
+  - chmod a+x lein
+  - export LEIN_ROOT=1
+  - PATH=$PATH:.
+  - lein deps
+  - lein migratus migrate
+
+test: 
+  script: 
+    - lein test
+```
+
+In before script we install JRE and [Leiningen](http://leiningen.org/). 
+Sample project uses [migratus](https://github.com/yogthos/migratus) library to manage database migrations. 
+So we added database migration as last step of `before_script` section
+
+You can use public runners available on `ci.gitlab.com` for testing your application with such configuration.

[Sid Sijbrandij]

Thanks @dzaporozhets