Gemfile in github-markup-1.0.2 vs Gemfile in github-markup-1.0.3

@@ -6,5 +6,6 @@
 gem "creole", "~>0.3.6"
 gem "wikicloth", "=0.6.0"
 gem "literati", "= 0.0.3"
 gem "asciidoctor", "= 0.1.4"
 gem "rake"
+gem "posix-spawn"