[travis] Enable rubocop

Author: waterlink

.travis.yml

@@ -9,5 +9,8 @@ rvm:
   - jruby-19mode
   - rbx
 
-script: bundle exec rspec
 bundler_args: --without development
+
+script:
+  - bundle exec rspec
+  - script/rubocop

Gemfile

@@ -6,7 +6,7 @@ group :test do
   gem "rspec"
   gem "rack-test"
   gem "webmock"
-  gem "rubocop"
+  gem "rubocop", :platform => [:ruby_20, :ruby_21, :ruby_22]
 end
 
 group :development, :test do

script/rubocop

@@ -0,0 +1,5 @@
+#/usr/bin/env bash
+
+if ruby -e 'exit(1) unless RUBY_VERSION.to_f >= 2.0'; then
+  bundle exec rubocop
+fi