* Add `invited_by` foreign key to User
Allows for a User to be tied to the user who invited them
* Include `current_user` in new agent initialization parameters
* Add `shoulda-matchers` for testing associations
* Add Inviter information and associated account to welcome email
* Only show inviter info if applicable
* Update conversation spec for FFaker compatibility
* Add Conversation factory with dependent factories
* Include FactoryBot methods in rspec config
* Add unit tests for public methods of Conversation model
* Move Current model into a separate file in lib folder
* Disable Metrics/BlockLength rule for db/migrate and spec folders
* Get rid of global $dispatcher variable
* Create Message#unread_since scope
* Refactor callback methods in Conversation model
* Create Conversations::EventDataPresenter
* Add translation keys for activity messages
* Add pry-rails gem
* Refactor Conversation#notify_status_change
* Add mock_redis for test env
