forces rubocop install in travis (#6167)

.travis.yml

@@ -65,6 +65,7 @@ install:
   - bash -c "if [ '$RAILS_MASTER' == '1' ]; then bundle update --retry=3 --jobs=3 arel rails seed-fu > /dev/null; fi"
   - bash -c "if [ '$RAILS_MASTER' == '0' ]; then bundle install --without development --deployment --retry=3 --jobs=3 > /dev/null; fi"
   - bash -c "if [ '$RUN_LINT' == '1' ]; then yarn global add eslint babel-eslint prettier > /dev/null; fi"
+  - bash -c "if [ '$RUN_LINT' == '1' ]; then gem install rubocop > /dev/null; fi"
   - bash -c "if [ '$QUNIT_RUN' == '1' ]; then yarn install --dev > /dev/null; fi"
   - bash -c "if [ '$RUN_LINT' != '1' ]; then bundle exec rake db:create db:migrate > /dev/null; fi"
 

Dangerfile

@@ -1,7 +1,3 @@
-require 'rubygems'
-require 'bundler'
-Bundler.require(:test)
-
 require 'json'
 require 'shellwords'