Include archival notice

README.md

@@ -1,5 +1,9 @@
 [![Build Status](https://travis-ci.org/infraling/atomic.svg?branch=development)](https://travis-ci.org/infraling/atomic)
 
+| :exclamation: |	**Repository will be archived soon!** |
+|-|-|
+|:warning:|Please note that Atomic is not developed anymore. It serves as architectural prototype for Hexatomic, which is currently under development at https://github.com/hexatomic/hexatomic.<br/>This repository will be archived soon!|
+
 # Atomic
 Software for multi-level annotation of linguistic corpora
 
@@ -15,4 +19,4 @@ Then there are also three Maven profiles, each of which builds a specific versio
 
 ### Build documentation
 
-Documentation is built separately from the product build. If you want to include up-to-date docs in the product build, build docs before product. Documentation has a [separate README](docs/org.corpus-tools.atomic.doc/README.md) with details on how to build.
+Documentation is built separately from the product build. If you want to include up-to-date docs in the product build, build docs before product. Documentation has a [separate README](docs/org.corpus-tools.atomic.doc/README.md) with details on how to build.