group :production do
gem 'bar', git: 'https://github.com/foo/bar', branch: 'master'
end
group :staging do
gem 'bar', git: 'https://github.com/foo/bar', branch: 'staging'
end
'hello world'.reverse.scan(/(.).{1}/).join
=> "drwol"
'hello world'.reverse.scan(/(.).{2}/).join
=> "doo"
--source http://rubygems.org
gem source -r https://rubygems.org/
gem source -a http://rubygems.org