add Getting Started section to README

When developing bio-nexml I had documented most of the API on NESCENT's
wiki. It's not complete, but definitely enough to get started.

README.rdoc

@@ -25,6 +25,12 @@ semantics) that is both easy to work with, yet ready for the Semantic Web.
 
 To learn more, visit http://www.nexml.org
 
+== Getting Started
+
+https://www.nescent.org/wg_phyloinformatics/NeXML_and_RDF_API_for_BioRuby
+
+It is not complete, but definitely enough to get started.
+
 == Contributing to bio-nexml
 
 * Check out the latest master to make sure the feature hasn't been implemented