Update continua.md

Add description for Continua CI

Author: GeertvanHorrik

docs/build-server-support/build-server/continua.md

@@ -0,0 +1,45 @@
+# Continua CI Setup
+
+This guide explains how to run GitVersion inside [Continua CI](https://www.finalbuilder.com/continua-ci).
+
+## Assumptions
+This guide assumes a few variables are present in the configuration. Note that this example uses `Catel` as repository name, but it should be replaced by the name of the repository where GitVersion is runnign against.
+
+* RepositoryBranchName => $Source.Catel.BranchName$ 
+* RepositoryCommitId => $Source.Catel.LatestChangeset.Id$ 
+* RepositoryName => Catel
+* RepositoryName => $Source.Catel.Path$
+* RepositoryUrl => $Source.Catel.Url$ 
+
+It also requires a few variables which will automatically be filled by GitVersion. The example below are just a few, any of the GitVersion variables written to the output can be used.
+
+* GitVersion_FullSemVer
+* GitVersion_MajorMinorPatch
+* GitVersion_NuGetVersion
+
+You also need to add a property collector for the agents to detect the GitVersion tool on the agents:
+
+* Namespace => GitVersion
+* Run On => Agent
+* Type => Path Finder Plugin
+* Property Name => Path
+* Executable => GitVersion.exe
+* Search paths => your installation folder (e.g. C:\Tools\GitVersion)
+
+## Basic Usage
+To run GitLink inside [Continua CI](https://www.finalbuilder.com/continua-ci), follow the steps below:
+
+* Add a new `Execute Program` step to a stage
+* In the `Execute Program` tab, set the following values:
+  * Executable path: $Agent.GitVersion.Path$
+  * Working directory: %RepositoryPath%
+* In the `Arguments` tab, set the following values:
+  * Arguments: /url %RepositoryUrl% /b %RepositoryBranchName% /c %RepositoryCommitId% /output buildserver
+* In the `Options` tab, set the following values:
+  * Wait for completion: checked
+  * Log output: checked
+  * Check program exit code: checked
+  * Exit code must be: equal to
+  * Exit code: 0
+  
+Now GitVersion will automatically run and fill the `GitVersion_` variables.