Adding pipeline info to README

README.md

 # GITLAB-CI EXAMPLE: MONO
 
+[![pipeline status](https://gitlab.com/tobiaskoch/gitlab-ci-example-mono/badges/master/pipeline.svg)](https://gitlab.com/tobiaskoch/gitlab-ci-example-mono/commits/master)
+
+---
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 This is a simple [gitlab continuous integration](https://about.gitlab.com/features/gitlab-ci-cd/) example project (compatible with the [shared runner](https://docs.gitlab.com/runner/) provided on [gitlab.com](https://gitlab.com)) using the official [mono docker image](https://hub.docker.com/_/mono/) to build a visual studio project.
 
 ## Contributing