<NME> rango.pre.gemspec
<BEF> ADDFILE
<MSG> Gemspec for prerelease

<DFF> @@ -0,0 +1,8 @@
+#!/usr/bin/env gem build
+# encoding: utf-8
+
+# You might think this is a terrible mess and guess what, you're
+# right mate! However say thanks to authors of RubyGems, not me.
+eval(File.read("rango.gemspec")).tap do |specification|
+  specification.version = "#{Rango::VERSION}.pre"
+end

Gemspec for prerelease