Add therubyrhino to dependencies

Gemfile

@@ -4,8 +4,6 @@ if RUBY_PLATFORM == 'java'
   gem 'warbler'
 end
 
-gem 'gollum-lib', :git => 'https://github.com/gollum/gollum-lib.git', :branch => 'gollum-lib-5.x' # For development purposes
-gem 'therubyrhino', :platforms => :jruby
 gemspec
 
 gem "rake", '~> 12.3', '>= 12.3.3'

gollum.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |s|
   s.rdoc_options = ['--charset=UTF-8']
   s.extra_rdoc_files = %w[README.md LICENSE]
 
-  s.add_dependency 'gollum-lib', '~> 5.0.a'
+  s.add_dependency 'gollum-lib', '~> 5.0'
   s.add_dependency 'kramdown', '~> 2.1.0'
   s.add_dependency 'kramdown-parser-gfm', '~> 1.0.0'
   s.add_dependency 'sinatra', '~> 2.0'
@@ -37,6 +37,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'uglifier', '~> 3.2'
   s.add_dependency 'sprockets-helpers', '~> 1.2'
   s.add_dependency 'rss', '~> 0.2.9'
+  s.add_dependency 'therubyrhino', '~> 2.1.0'
 
   s.add_development_dependency 'rack-test', '~> 0.6.3'
   s.add_development_dependency 'shoulda', '~> 3.6.0'

lib/gollum.rb

@@ -6,6 +6,7 @@ require 'ostruct'
 
 # external
 require 'github/markup'
+require 'rhino' if RUBY_PLATFORM == 'java'
 
 # internal
 require File.expand_path('../gollum/uri_encode_component', __FILE__)