Add modern Gemfile based on gareth skeleton

Gemfile

@@ -1,14 +1,37 @@
-source 'https://rubygems.org'
+source ENV['GEM_SOURCE'] || "https://rubygems.org"
 
-if ENV.include?('PUPPET_VERSION')
-  puppetversion = "~>#{ENV['PUPPET_VERSION']}"
-else
-  puppetversion = '~>4.5.0'
+group :test do
+  gem "rake", '< 11.0'
+  gem "puppet", ENV['PUPPET_GEM_VERSION'] || '~> 3.8.0'
+  gem "rspec", '<= 3.1.0'
+  gem "rspec-puppet"
+  gem "puppetlabs_spec_helper"
+  gem "metadata-json-lint"
+  gem "rspec-puppet-facts"
+  gem 'rubocop', '0.33.0'
+  gem 'simplecov', '>= 0.11.0'
+  gem 'simplecov-console'
+
+  gem "puppet-lint-absolute_classname-check"
+  gem "puppet-lint-leading_zero-check"
+  gem "puppet-lint-trailing_comma-check"
+  gem "puppet-lint-version_comparison-check"
+  gem "puppet-lint-classes_and_types_beginning_with_digits-check"
+  gem "puppet-lint-unquoted_string-check"
+  gem 'puppet-lint-resource_reference_syntax'
+
+  gem 'json_pure', '<= 2.0.1' if RUBY_VERSION < '2.0.0'
 end
 
-gem 'rake'
-gem 'puppet', puppetversion
-gem 'puppet-lint'
-gem 'rspec-puppet'
-gem 'puppetlabs_spec_helper'
-gem 'metadata-json-lint'
+group :development do
+  gem "travis" if RUBY_VERSION >= '2.1.0'
+  gem "travis-lint" if RUBY_VERSION >= '2.1.0'
+  gem "puppet-blacksmith"
+  gem "guard-rake" if RUBY_VERSION >= '2.2.5' # per dependency https://rubygems.org/gems/ruby_dep
+end
+
+group :system_tests do
+  gem "beaker"
+  gem "beaker-rspec"
+  gem "beaker-puppet_install_helper"
+end