Update spd.md

added license #34 as part of metadata updates

ontology/spd.md

@@ -4,6 +4,9 @@ id: spd
 contact:
   email: [email protected]
   label: Martin Ramirez
+license:
+  url: https://creativecommons.org/licenses/by/3.0/
+  label: CC-BY 3.0
 description: An ontology for spider comparative biology including anatomical parts (e.g. leg, claw), behavior (e.g. courtship, combing) and products (i.g. silk, web, borrow).
 domain: anatomy
 homepage: http://research.amnh.org/atol/files/