docs: describe pipelines

README.md

@@ -6,12 +6,16 @@ hosted on the gitlab server.
 
 ## CTA
 
+This pipeline builds and produces rpms for CTA project.
 [![pipeline status](https://gitlab.desy.de/dcache/cta/badges/master/pipeline.svg)](https://gitlab.desy.de/dcache/cta/-/commits/master)
 
+
 ## dCache
 
+This pipeline builds and produces rpm,deb and tar packages for dCache.
 [![pipeline status](https://gitlab.desy.de/dcache/cta/badges/master/pipeline.svg)](https://gitlab.desy.de/dcache/dcache/-/commits/master)
 
 ## nfs4j
 
+This pipeline builds dCache's NFS4J standalone library
 [![pipeline status](https://gitlab.desy.de/dcache/cta/badges/master/pipeline.svg)](https://gitlab.desy.de/dcache/nfs4j/-/commits/master)
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