Gemfile: add therubyracer

Signed-off-by: May <sirhuntthepure@users.noreply.github.com>
lib: add library for communicating with candlepin

APIs are dynamically defined from configuration file.

Signed-off-by: May <sirhuntthepure@users.noreply.github.com>
config: add candlepin initializer

And a test Rails constant.

Signed-off-by: May <sirhuntthepure@users.noreply.github.com>