Delete missing static recurring tasks before loading them again

Closes #382 and #420.

Author: rosa

lib/solid_queue/scheduler/recurring_schedule.rb

@@ -41,6 +41,7 @@ def task_keys
 
     private
       def persist_tasks
+        SolidQueue::RecurringTask.static.where.not(key: task_keys).delete_all
         SolidQueue::RecurringTask.create_or_update_all configured_tasks
       end
 

test/integration/recurring_tasks_test.rb

@@ -64,13 +64,13 @@ class RecurringTasksTest < ActiveSupport::TestCase
     scheduler1 = SolidQueue::Scheduler.new(recurring_tasks: another_task).tap(&:start)
     wait_for_registered_processes(6, timeout: 1.second)
 
-    assert_recurring_tasks configured_task.merge(another_task)
+    assert_recurring_tasks another_task
 
     updated_task = { example_task: { class: "AddToBufferJob", schedule: "every minute" } }
     scheduler2 = SolidQueue::Scheduler.new(recurring_tasks: updated_task).tap(&:start)
     wait_for_registered_processes(7, timeout: 1.second)
 
-    assert_recurring_tasks configured_task.merge(updated_task)
+    assert_recurring_tasks updated_task
 
     terminate_process(@pid)
     scheduler1.stop