The public_suffix gem (invoked by addressable and used in

some of the http clients tested) no longer supports Ruby 2.0.0
and breaks Travis CI under 2.0.0 test.

In practice, not all http clients have this dependency, so I
didn't want to put this restriction in the httpi.gemspec.

Other options are to remove 2.0.0 from travis.yml and update the
httpi.gemspec to require ruby >= 2.1.0, but this requires more
discussion.

Gemfile

@@ -3,6 +3,9 @@ gemspec
 
 gem 'jruby-openssl',                                       :platforms => :jruby
 
+# compatibility restrictions for http clients under existing travis test environments
+gem 'public_suffix', '~> 2.0'   # or remove rubies < 2.1 from travis.yml
+
 # http clients
 gem 'httpclient',          '~> 2.3',    :require => false
 gem 'curb',                '~> 0.8',    :require => false, :platforms => :ruby