[ZH/CR][71159472] Add rspec-rails
[ZH/CR][71159472] Add Foreman and setup Procfile

Pivotal Story: https://www.pivotaltracker.com/story/show/71159472
[ZH/CR][71159472] Add .env.dev sample and .env.test

Pivotal Story: https://www.pivotaltracker.com/story/show/71159472
[ZH/CR][71159472] Fix foreman env setting
[ZH/CR][71159472] Initial implementation of worker queueing
[ZH/CR][71159472] Remove json payload info from README
[ZH/CR][71159472] Implement Queue and add linewise commenting

Pivotal Story: https://www.pivotaltracker.com/story/show/71159472

- Adds RabbitMQ for background jobs
- Posts linewise comments on PRs
Merge branch 'ZH_CR_71159472_implement_queuing'