Add Zenodo DOI Badge

Change-Id: I846a351bbbda77e2ffd3a54bbf8a5a2469f56a1f
diff --git a/README.md b/README.md
index 92d2de4..5d03dd9 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
 ![Kustvakt](https://raw.githubusercontent.com/KorAP/Kustvakt/master/misc/kustvakt.png)
 
+[![DOI](https://zenodo.org/badge/104361763.svg)](https://zenodo.org/badge/latestdoi/104361763)
+
 Kustvakt is a user and policy management component for KorAP (Diewald et al., 2016). It manages user access to resources (i.e. corpus data) typically bound with some licensing schemes. The licensing schemes of IDS resources provided through KorAP (DeReKo) are very complex involving the user access location and purposes (Kupietz & Lüngen, 2014). To manage user access to resources, Kustvakt performs query rewriting with document restrictions (BaƄski et al., 2014).
 
 Kustvakt acts as a middleware in KorAP binding other components, such as [Koral](https://github.com/KorAP/Koral) a query serializer and [Krill](https://github.com/KorAP/Krill) a search component, together. As the KorAP's API provider, it provides services, e.g. searching and retrieving annotation data of a match/hit, that can be used by a KorAP client, e.g. [Kalamar](https://github.com/KorAP/Kalamar) (a KorAP web user interface) and [KorapSRU](https://github.com/KorAP/KorapSRU) (the CLARIN FCS endpoint for KorAP).