Added dotenv-rails and gibbon gems to Gemfile
Added sidekiq gem for background processes
Added publish column to compilations
Added redis-semaphore gem
Added mailchimp config initializer with yaml example file
Added code to mark a compilation for publishing on the client side
Added mailchimp api key to mailchimp yaml config example
Added render_anywhere gem
Fixed mailchimp config initializer to read yaml files with embedded erb code
Added redcarpet gem
Added layout and template to use them for rendering the newsletter
Added compilation publisher service object responsible of creating the mailchimp campaign and deliver it to subscribers using mailchimp api
Added sidekiq worker responsible of publishing a compilation
Merge branch 'feature/compilation-publishing'