feat: new background work process

This removes all previous dependencies on RabbitMQ and the need to run separate cron and requeueing processes.

app/models/concerns/has_locking.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+# This concern provides functionality for locking items along with additional functionality to handle
+# the concept of retrying items after a certain period of time. The following database columns are
+# required on the model
+#
+# * locked_by - A string column to store the name of the process that has locked the item
+# * locked_at - A datetime column to store the time the item was locked
+# * retry_after - A datetime column to store the time after which the item should be retried
+# * attempts - An integer column to store the number of attempts that have been made to process the item
+#
+# 'ready' means that it's ready to be processed.
+module HasLocking
+
+  extend ActiveSupport::Concern
+
+  included do
+    scope :unlocked, -> { where(locked_at: nil) }
+    scope :ready, -> { where("retry_after IS NULL OR retry_after < ?", Time.now) }
+  end
+
+  def ready?
+    retry_after.nil? || retry_after < Time.now
+  end
+
+  def unlock
+    self.locked_by = nil
+    self.locked_at = nil
+    update_columns(locked_by: nil, locked_at: nil)
+  end
+
+  def locked?
+    locked_at.present?
+  end
+
+  def retry_later(time = nil)
+    retry_time = time || calculate_retry_time(attempts, 5.minutes)
+    self.locked_by = nil
+    self.locked_at = nil
+    update_columns(locked_by: nil, locked_at: nil, retry_after: Time.now + retry_time, attempts: attempts + 1)
+  end
+
+  def calculate_retry_time(attempts, initial_period)
+    (1.3**attempts) * initial_period
+  end
+
+end

app/models/concerns/has_soft_destroy.rb

@@ -14,7 +14,6 @@ module HasSoftDestroy
     run_callbacks :soft_destroy do
       self.deleted_at = Time.now
       save!
-      ActionDeletionJob.queue(:main, type: self.class.name, id: id)
     end
   end