Require at least CGI 0.3.6

Since it accepts apex domains (.example.com) for cookie domains.
Otherwise there can be errors with certain rails/ruby versions when using domains: :all

activerecord-session_store.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.add_dependency('railties', '>= 6.1')
   s.add_dependency('rack', '>= 2.0.8', '< 3')
   s.add_dependency('multi_json', '~> 1.11', '>= 1.11.2')
+  s.add_dependency('cgi', '>= 0.3.6')
 
   s.add_development_dependency('sqlite3')
 end