added citation metadata

Author: jspaaks

.zenodo.json

@@ -0,0 +1,28 @@
+{
+    "creators": [
+        {
+            "affiliation": "Netherlands eScience Center",
+            "name": "Spaaks, Jurriaan H.",
+            "orcid": "0000-0002-7064-4069"
+        },
+        {
+            "affiliation": "Netherlands eScience Center",
+            "name": "Maassen, Jason",
+            "orcid": "0000-0002-8172-4865"
+        },
+        {
+            "affiliation": "Netherlands eScience Center",
+            "name": "Verhoeven, Stefan",
+            "orcid": "0000-0002-5821-2060"
+        },
+        {
+            "affiliation": "Netherlands eScience Center",
+            "name": "Hidding, Johan"
+        }
+    ],
+    "description": "Source files for a tutorial about xenon.",
+    "license": {
+        "id": "Apache-2.0"
+    },
+    "title": "xenon tutorial"
+}

CITATION.cff

@@ -0,0 +1,32 @@
+# YAML 1.2
+---
+abstract: "Source files for a tutorial about xenon."
+authors: 
+  -
+    affiliation: "Netherlands eScience Center"
+    family-names: Spaaks
+    given-names: "Jurriaan H."
+    orcid: "https://orcid.org/0000-0002-7064-4069"
+  -
+    affiliation: "Netherlands eScience Center"
+    family-names: Maassen
+    given-names: Jason
+    orcid: "https://orcid.org/0000-0002-8172-4865"
+  -
+    affiliation: "Netherlands eScience Center"
+    family-names: Verhoeven
+    given-names: Stefan
+    orcid: "https://orcid.org/0000-0002-5821-2060"
+  -
+    affiliation: "Netherlands eScience Center"
+    family-names: Hidding
+    given-names: Johan
+cff-version: "1.0.3"
+date-released: 2019-09-04
+doi: "10.5281/zenodo.1064653"
+license: "Apache-2.0"
+message: "If you use this software, please cite it using these metadata."
+repository-code: "https://github.com/xenon-middleware/xenon-tutorial"
+title: "xenon tutorial"
+version: "3.0.1"
+...