* [#139] Delayed emails for conversations
* Added the setex and get methods to Redis wrapper
* Set the priorities for the sidekiq queues
* Was not able to use mailhog for testing email in local, switched back to letter opener and added comments on using the SMTP settings
* Added after create hood in messages to queue the sending of mail after 2 minutes using sidekiq worker and also set the redis key for the conversation to avoid the email sending for every message
* Added the sidekiq worker to send the email and delete the conversation redis key
* Added the mailer and mail template
* mailer sends the last 10 messages along with the new messages from the time it was queued
* Send email only in development or if smtp config is set
* Send email only in development or if smtp config is set
* Set the SMTP_PORT in production variable
* Adding redis to circle CI
* Specs for the conversation email changes
* Added specs for conversation email sidekiq worker
* Added specs for conversation mailer
* Added specs in message model for the after create hook for notify email
* Send emails only when there is a reply from agent
* set development to use mailhog
* Adding comments for using letter opener
* add sidekiq web view if the user is an administrator
* add sidekiq setup configuration and support
* update devise to use delivery_later method and update test
* update conversation to use deliver_later instead of deliver
* Update Routes
* Add Procfile for Heroku One-Click Start
* updating docs
* update concurrency and Procfile for supporting Heroku Free Dyno
* update Procfile.dev
