Fix CI failures

Author: mshibuya

carrierwave.gemspec

@@ -48,5 +48,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "timecop"
   s.add_development_dependency "generator_spec", ">= 0.9.1"
   s.add_development_dependency "pry"
-  s.add_development_dependency "pry-byebug"
+  if RUBY_ENGINE != 'jruby'
+    s.add_development_dependency "pry-byebug"
+  end
 end

gemfiles/rails-5-0.gemfile

@@ -4,5 +4,8 @@ gem "rails", "~> 5.0.0"
 gem 'pg', '~> 0.21.0', platforms: :ruby
 gem "activemodel-serializers-xml"
 gem "activerecord-jdbcpostgresql-adapter", "~> 50.0", platforms: :jruby
+if RUBY_VERSION < '2.3'
+  gem "ruby-vips", "2.0.13"
+end
 
 gemspec :path => "../"