Do not have users require cgi

[sri]

It seems strange to require users to require the cgi module in their gem file:

require "cgi" source "http://localhost:9042/upstream/#{CGI.escape("http://127.0.0.1:9043")}"

Instead provide a better way with gemstash:

require "gemstash/bundler" gemstash_source "http://localhost:9042/upstream", "http://127.0.0.1:9043"

Or perhaps:

require "gemstash/bundler" gemstash_url "http://localhost:9042" source gemstash_upstream("http://127.0.0.1:9043")

[smellsblue]

:+1: