Adding CFF file to enable Software citation

CITATION.cff

@@ -0,0 +1,20 @@
+# YAML 1.2
+---
+authors: 
+  -
+    family-names: Karunanithi
+    given-names: Sivarajan
+    orcid: "https://orcid.org/0000-0001-6128-5351"
+  -
+    family-names: Simon
+    given-names: Martin
+    orcid: "https://orcid.org/0000-0002-0962-7788"
+  -
+    family-names: Schulz
+    given-names: Marcel
+    orcid: "https://orcid.org/0000-0002-1252-3656"
+cff-version: "1.0.3"
+message: "If you use this software, please cite it using these metadata."
+repository-code: "https://github.com/SchulzLab/RAPID"
+title: "Automated analysis of small RNA datasets with RAPID"
+...