bolognese.gemspec in bolognese-0.9.56 vs bolognese.gemspec in bolognese-0.9.58

@@ -22,9 +22,10 @@
   s.add_dependency 'activesupport', '>= 4.2.5', '< 6'
   s.add_dependency 'bibtex-ruby', '~> 4.1'
   s.add_dependency 'thor', '~> 0.19'
   s.add_dependency 'colorize', '~> 0.8.1'
   s.add_dependency 'namae', '~> 0.11.3'
+  s.add_dependency 'iso8601', '~> 0.9.1'
   s.add_dependency 'postrank-uri', '~> 1.0', '>= 1.0.18'
   s.add_dependency 'json-ld', '~> 2.1', '>= 2.1.2'
   s.add_dependency 'jsonlint', '~> 0.2.0'
   s.add_dependency 'oj', '>= 2.8.3'
   s.add_dependency 'rdf-turtle', '~> 2.2'