CI setup docs

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

doc/development/README.md

@@ -3,3 +3,4 @@
 - [Architecture](architecture.md) of GitLab
 - [Shell commands](shell_commands.md) in the GitLab codebase
 - [Rake tasks](rake_tasks.md) for development
+- [CI setup](ci_setup.md) for testing GitLab

doc/development/ci_setup.md

+# CI setup
+
+This document describes what services we use for testing GitLab and GitLab CI. 
+
+What services we currently use for testing GitLab: 
+
+### GitLab CI at ci.gitlab.org
+
+We use it for testing software from private server at dev.gitlab.org
+
+### Semaphore at semaphoreapp.com
+
+We use for testing Pull requests and builds from our mirror on github.com
+
+### GitLab CI at gitlab-ce.githost.io
+
+We use it for testing our repository at gitlab.com
+
+
+## Table of CI usage 
+
+
+| Software                              | GitLab CI (ci.gitlab.org) | GitLab CI (githost.io) | Semaphore |
+|---------------------------------------|---------------------------|------------------------|-----------|
+| GitLab CE @ MySQL                     | ✓                         | ✓                      |           |
+| GitLab CE @ PostgreSQL                |                           |                        | ✓         |
+| GitLab EE @ MySQL                     | ✓                         |                        |           |
+| GitLab CI @ MySQL                     | ✓                         |                        |           |
+| GitLab CI @ PostgreSQL                |                           |                        | ✓         |
+| GitLab CI Runner                      | ✓                         |                        | ✓         |
+| GitLab Shell                          | ✓                         |                        | ✓         |
+| GitLab Shell                          | ✓                         |                        | ✓         |