Update cron documentation to remove confusion about multiple processes (

#1467)

README.md

@@ -613,9 +613,7 @@ GoodJob's concurrency control strategy for `perform_limit` is "optimistic retry
 
 GoodJob can enqueue Active Job jobs on a recurring basis that can be used as a replacement for cron.
 
-Cron-style jobs can be performed by any GoodJob process (e.g., CLI or `:async` execution mode) that has `config.good_job.enable_cron` set to `true`. That is, one or more job executor processes can be configured to perform recurring jobs.
-
-GoodJob's cron uses unique indexes to ensure that only a single job is enqueued at the given time interval. In order for this to work, GoodJob must preserve cron-created job records; these records will be automatically deleted like any other preserved record.
+Cron-style jobs can be enequeued by any GoodJob process (e.g., CLI or `:async` execution mode) that has `config.good_job.enable_cron` set to `true`. Enabling cron on multiple processes will not enqueue duplicate jobs; GoodJob's cron uses unique indexes to ensure that only a single job is enqueued for a given time interval.  In order for this to work, GoodJob must preserve cron-created job records; these records will be automatically deleted like any other preserved record.
 
 Cron-format is parsed by the [`fugit`](https://github.com/floraison/fugit) gem, which has support for seconds-level resolution (e.g. `* * * * * *`) and natural language parsing (e.g. `every second`).
 
@@ -624,8 +622,8 @@ If you use the [Dashboard](#dashboard) the scheduled tasks can be viewed in the
 ```ruby
 # config/environments/application.rb or a specific environment e.g. production.rb
 
-# Enable cron in this process, e.g., only run on the first Heroku worker process
-config.good_job.enable_cron = ENV['DYNO'] == 'worker.1' # or `true` or via $GOOD_JOB_ENABLE_CRON
+# Enable cron enqueuing in this process
+config.good_job.enable_cron = true
 
 # Configure cron with a hash that has a unique key for each recurring job
 config.good_job.cron = {