Merge pull request #17846 from biow0lf/bump-ruby-version

Bump ruby version to 2.1.0 in rails.gemspec too.

rails.gemspec

@@ -7,7 +7,7 @@
   s.summary     = 'Full-stack web application framework.'
   s.description = 'Ruby on Rails is a full-stack web framework optimized for programmer happiness and sustainable productivity. It encourages beautiful code by favoring convention over configuration.'
 
-  s.required_ruby_version     = '>= 1.9.3'
+  s.required_ruby_version     = '>= 2.1.0'
   s.required_rubygems_version = '>= 1.8.11'
 
   s.license = 'MIT'