Merge pull request activeadmin#1827 from nbibler/master

Add the license identifier to the gemspec

Author: pcreux

activeadmin.gemspec

@@ -4,6 +4,7 @@ require "active_admin/version"
 
 Gem::Specification.new do |s|
   s.name          = %q{activeadmin}
+  s.license       = "MIT"
   s.version       = ActiveAdmin::VERSION
   s.platform      = Gem::Platform::RUBY
   s.homepage      = %q{http://activeadmin.info}