Always use `newrelic_rpm` [ci skip]

Provides developer mode for viewing metrics in development.
Add unicorn
Setup `config/unicorn.rb`

Use `dotenv` gem to read `.env` file and update it when the server
starts or restarts. Configure number of unicorn workers via `ENV`
variable.
Add unicorn deploy tasks
Update .env.sample
Add `PtsMembership` command

Shells out to `pts` command line utility for checking members of
specified AFS group. Handles when command has a 0 exit status but
returns an error message.
Add worker to sync users that have the desk worker role

Runs every 5 minutes. Notifies `Honeybadger` if
`ENV['DESK_WORKERS_GROUP']` is missing or if the command failed.
Extract meaningful methods in SyncRolesWorker