Explicitlly require 'delegate' and add example for #92.

Author: gkellogg

examples/issue92.rb

@@ -0,0 +1,8 @@
+require 'rdf'
+require 'sparql/client'
+dnbt = RDF::Vocabulary.new("https://d-nb.info/standards/elementset/dnb#")
+rdf_gndid = RDF::Literal.new("https://d-nb.info/gnd/1059461498")
+sparql_client = SPARQL::Client.new("http://127.0.0.1:9292/")
+gndo = RDF::Vocabulary.new("http://d-nb.info/gnd/standards/elementset/gnd#")
+query = sparql_client.select.where([:subject, dnbt.deprecatedUri, rdf_gndid]).where([:subject, gndo.gndIdentifier, :gndid])
+query.each_solution { |solution| new_gndid = solution[:gndid].to_s }

lib/sparql/client/query.rb

@@ -1,3 +1,5 @@
+require 'delegate'
+
 class SPARQL::Client
   ##
   # A SPARQL query builder.