maintenance: add job to check for database corruption.

Add a job to run pg_amcheck hourly to check for corrupt database indexes.

https://www.postgresql.org/docs/14/app-pgamcheck.html

test/jobs/amcheck_database_job_test.rb

@@ -0,0 +1,9 @@
+require 'test_helper'
+
+class AmcheckDatabaseJobTest < ActiveJob::TestCase
+  context "AmcheckDatabaseJob" do
+    should "work" do
+      AmcheckDatabaseJob.perform_now
+    end
+  end
+end