Merge branch 'dewet-do-disclaimer' into 'master'

Disclaimer for testing guide not be be used in prod

See merge request !10468

doc/install/README.md

@@ -20,8 +20,8 @@ the hardware requirements.
 - [Docker](https://docs.gitlab.com/omnibus/docker/) - Install GitLab using Docker.
 - [Installation on Google Cloud Platform](google_cloud_platform/index.md) - Install
   GitLab on Google Cloud Platform using our official image.
-- [Digital Ocean and Docker](digitaloceandocker.md) - Install GitLab quickly
-  on DigitalOcean using Docker.
+- Testing only! [DigitalOcean and Docker Machine](digitaloceandocker.md) -
+  Quickly test any version of GitLab on DigitalOcean using Docker Machine.
 ## Database

doc/install/digitaloceandocker.md

-# Digital Ocean and Docker
+# Digital Ocean and Docker Machine test environment
+
+## Warning. This guide is for quickly testing different versions of GitLab and
+## not recommended for ease of future upgrades or keeping the data you create.
 ## Initial setup